More than half of all U.S. adults under the age of 60 have used cannabis at least once. While cannabis is usually smoked, oral consumption is not uncommon. When eaten, the effects take substantially more time to come on, are described as being more intense, and last hours longer than when smoked. The high potency of THC and other cannabinoids means that a large dose can fit into a tiny portion of food. These factors, combined with a wide variation in potency from one batch of edibles to another, present a considerable risk of unpleasant, long-lasting, accidental overdoses.

Cannabis edibles have become more available in recent years as the medical marijuana market has matured. They are popular enough that a page with two recipes for cannabis cookies was the third most visited article on Erowid.org in August and September 2011. Many medical dispensaries sell an assortment of edible products: from classic brownies and cookies, to fudges, lollipops, pizzas, bagel bites, tinctures, and "cannabutter" (for use in home cooking).

But even commercially available products are made from plants that naturally vary in cannabinoid concentrations. Whether bought or baked at home, the dosage of the same type of edible can differ from one batch to the next. As a result of this natural variation, as well as some common usage errors, over the past 40 years oral cannabis has developed a reputation for being unpleasant and too strong. An overdose can be overwhelming, including extreme disorientation, confusion, hallucinations, depersonalization, nausea, vomiting, pounding heart, anxiety, and paranoia.

It's a familiar story. A student unaccustomed to oral cannabis is offered a pot brownie at a dorm party or festival, and ends up getting radically more than he or she bargained for.

Many people swear off ingesting cannabis after such an experience. Achieving just the right degree of effect from a proffered edible is difficult, even for those with extensive experience.

Yet, careful oral consumption can provide benefits over smoking, including reduced throat and lung irritation, and longer duration, which results in less frequent need to redose and greater consistency in intensity over time.

Some regular users of oral cannabis, such as medical marijuana patients, have developed personal protocols for achieving consistent results with various preparations. As vendors selling edible cannabis products multiply and reports of classic consumption errors continue to prevail, it's important to document the various techniques for successfully working with oral cannabis.

Several easily avoidable mistakes are the primary causes of most oral cannabis overdoses. As long as a few guidelines are kept in mind, cannabis edibles can be used safely, providing an effective--and in some ways preferable--alternative to smoking.

With key differences in dose, onset, duration, and methodology, it may be useful to think of oral cannabis as a different drug than smoked cannabis. Even frequent smokers can easily overdose when consuming orally. The slow onset and extended duration often surprise those who are only familiar with smoking or vaporizing.

THC is orally active in the range of a few milligrams (6 milligrams of THC without daily-use tolerance can get a person REALLY high), while a cookie or brownie typically weighs more than 10 grams. That means it's easy for nearly any cannabis-infused edible to range in potency from inactive to strong enough to induce a radical overdose. Unless one has personally established the strength of a particular batch of edibles, there's no immediate way to determine how strong it is. Without checking it first, an edible cannabis preparation should be considered potentially highly potent.

Because expectations, tolerance, and reactions can vary dramatically from one person to the next, relying on someone else's description of potency is a recipe for disaster. Those who make oral cannabis products are more likely to be regular users who have built up a tolerance, and therefore they often underestimate potency for first-time or casual consumers. The size of a cookie or brownie provides no reliable clues: a powerful oral dose can fit into the size of a small tablet and it's unfortunately common for a reasonable dose to be a quarter or less of a cookie, brownie, or crispy treat.

Establishing the strength of the material for yourself, by starting very low, before you ingest a full dose is the fundamental key to the L.E.S.S. method. If one is faced with an edible of unknown potency, and yet is determined to try it, the best way to avoid an overdose is to intentionally underdose. Begin with a small piece (less than a quarter of a suggested portion). Measure or weigh the piece you try and make note of it. Then wait a minimum of 90 minutes on an empty stomach, or 120-150 minutes otherwise, before evaluating whether or not to consume another small piece.

Depending on amount consumed, metabolism, and how recently a person has eaten, oral cannabis can take 30-120 minutes to initially be felt, and can last from three hours to more than 24 hours at high doses. Duration increases with dose, so it's critical to wait after trying a piece of an edible before adding more. Countless stories document people redosing shortly before the full-blown effects of their first dose kicked in.

Experimenters should consider whether they have enough time and patience to establish the potency of an untested edible: with 90-120 minutes for the first check-in, it could be three to four hours before the desired level is reached, and then another three to six hours back to baseline. If there are time constraints, the more responsible choice is to not redose with edibles and just enjoy whatever effects occur. If you don't have the time to be patient, perhaps it's not the right time to eat cannabis.

When experimenting with new edibles, start sober. The likelihood of overdosing on oral cannabis is significantly increased if one is already high from smoked/vaporized cannabis or drunk on alcohol.
A low oral dose makes a good base. Once the effects are felt and have evened out, smoked or vaporized cannabis can be added to increase effects as desired. This method reduces negative impact on lungs and breathing while still allowing the dose to be titrated closely. It makes it practical to "underdose" with oral cannabis without having the experience be disappointing.

If supplementing with smoked or vaporized cannabis, wait a few minutes between tokes. The underlying oral cannabis can cause an unexpected acceleration of intensity.

Cannabis edibles are not food--they're drug delivery devices. Because of problems of accidental ingestion and overdosing, ideal edibles for recreational use are not ultra yummy, nor do they look enticingly delicious. It's better if a user doesn't eat too much of the edible simply because they're tasty. When the munchies kick in, the cannabis-laden food shouldn't be anywhere on the list of available snacks. The target is palatable medicine, not food.

If making your own edibles, don't cut them into regular cookie- or brownie-sized pieces, and, whenever possible, clearly label them to avoid accidental ingestion. Very small and/or irregularly shaped pieces will both reduce the chance of overdose and make it more likely that a friend will realize they're not for snacking. The risk of overdose is especially high for an unsuspecting visitor. Guests shouldn't be tempted to unknowingly consume several cookies in the middle of the night, mistaking them for dessert.

When working with edibles, making (or buying) larger batches allows for more consistent dosing over time. Starting low and carefully measuring is less useful if there are only one or two doses per batch. But if a batch contains 20 or more doses, once the appropriate level has been determined, weighing a piece from the same batch can provide a similar level of effects each time.

Put simply, oral cannabis can be used safely and effectively by consuming just enough to reach a low level of effects, redosing with small amounts as necessary (no more often than every 90 minutes), treating it as a drug and not a food, working with larger batches of confirmed potency, and supplementing with small amounts of smoked or vaporized cannabis to reach the desired level.

Mixing bowl, baking sheet, small metal sieve, small saut&eactue; pan.

* Edibles Can Utilize Weak Material

One benefit of oral preparations is that they can make use of weak cannabis material such as leaves, or buds that have already been run through a vaporizer. There are still active cannabinoids left in depleted plant material after vaporization. Some people are tempted to increase the temperature on their vaporizer to minimize the waste, but this defeats some of the health benefits of using these devices. While ash from pipes or bongs is not useful in making cannabis edibles (even small amounts will ruin the flavor), weak or depleted cannabis is excellent for use in oral preparations.

6 g cannabis (fresh bud, shake, leaves, or post-vaporized*)

¼ lb (113 g) butter

3 cups (710 ml) flour

1 cup (235 ml) sugar

Choose a recipe that suits your tastes, remembering that it should not be for a common food that a stoned person might eat. Ginger snaps or other strongly flavored items work well, both to avoid over-snacking and to mask the flavor of cannabis in the final product. Using a boxed mix, while convenient, is especially likely to result in a product that is too easy to mistake for a snack.

Replace the butter in the chosen recipe with the cannabis butter as prepared below. The recipe should use approximately ¼ lb (1 stick) of butter per 3 cups of flour and 1 cup of sugar (or per 4 cups of total dry material) to match this template. If the recipe varies from those proportions, the dose needs to be adjusted accordingly.

Cannabis is ground or minced thoroughly. Butter is cut into thirds. The cannabis is browned at medium heat in one third of the butter and thoroughly saturated in liquid butter for several minutes. Stir frequently. Do not walk away or use too much heat, as the cannabis can burn quickly.

The liquidy mixture of butter and cannabis is poured into the sieve and pressed with a spoon, draining the liquid butter into a mixing bowl and retaining the cannabis in the sieve. Repeat this extraction process two more times, re-browning the same cannabis in one third of the butter each time.

After three extractions, nearly all of the cannabinoids are now in the butter, and the plant material can be discarded. If the recipe is strongly flavored, the remaining cannabis plant material could be added back into the product; however, don't try this the first time you make the recipe, as it may produce unpleasant-tasting results.

Use the resulting cannabis butter in your selected recipe, label the final product with a clear warning, and store out of the reach of children.

Scale accurate to 0.1 gram, clock, notepad.

After a batch is first created, it is critical to try it at a dose well below what you have used before with other batches. If you have never previously tried this approach, start with about 1 gram of final baked product (assuming use of the L.E.S.S. recipe template). If you have used the procedure before, start with half the mass that you predict would be a low dose. This creates a safety margin in case the cannabis is unexpectedly strong. Keep in mind that the goal is to hit a low level of effects: underdosing is not an error, it's the target. Record the weight of the sample dose, the time, and--once the effects manifest fully--the approximate strength. Variants of "strong", "medium", and "weak" are sufficient for this purpose.

Using the L.E.S.S. recipe template, 1-5 grams of the resulting baked goods will contain a moderate dose for an experienced, non-tolerated cannabis user.

Forgetfulness is normal and expected with cannabis consumption. During a test, always write down how much was consumed and when, so you can double-check before redosing. Keep a clock and notepad next to your scale. Once you're in the habit of glancing at the clock and taking quick notes, it becomes easy and natural.

Vocalizing is a powerful mnemonic aid. If you're intending to take multiple doses over the course of an evening, consider saying the time out loud whenever a dose is weighed and consumed. This can help remind you to note the time and amount. It's especially useful when working with others who might then remind the weigher to make the record. If you discover that you forgot to write down a previous dose, enter a guess with a question mark and wait a little longer before redosing. Maybe you're higher than you think.

On an empty stomach, the effects come on fully between 60 and 150 minutes; on a full stomach they can take up to four hours to manifest. To maintain a given level, another dose of cannabis edible can be taken around 120 minutes after the previous dose (plus or minus 20 minutes depending on whether the previous dose was stronger or weaker than intended). Remember, redosing too early is likely to result in overly strong effects.

If experimenting with eating cannabis, be conservative. The common overdose errors associated with oral cannabis consumption can leave a lasting sense of trauma that nobody wants to experience.