Cannabis sativa, more commonly referred to as marijuana, is the second most commonly used recreational drug in the United States after alcohol. A number of states have adopted measures to decriminalize marijuana and legalize its use for both medicinal purposes and recreational purposes. Despite this trend, the United States Drug Enforcement Administration (DEA) still classifies marijuana as a Schedule I controlled substance. This classification indicates that the DEA, as well as the federal government, still considers marijuana to be a substance without significant medicinal uses and one that has a high potential to be abused and to result in the development of psychological and/or physical dependence.

The debate on the benefits and potential dangers of using marijuana still continues in a number of different forums. One interesting aspect of this debate is the question on whether or not one can overdose using marijuana.

Is a Fatal Overdose Due to Marijuana Possible?


The general consensus is that one cannot suffer an overdose on marijuana. The sources that support this answer define the term overdose as a potentially fatal or seriously physically damaging condition associated with excessive intake of a particular substance. The sources cite some important and essentially accurate reasons for their justification. These reasons include:

  • Active ingredients: The primary psychoactive ingredient in cannabis is delta-9-tetrahydrocannabinol,more commonly referred to as THC. The majority of information regarding the effects and toxicity of cannabis refers to amounts of THC and not other psychoactive substances in cannabis. This article will restrict the discussion to issues surrounding THC.
  • Neurophysiology: The brain has built-in receptors that have a high affinity for THC. These receptors are known as cannabinoid receptors, and THC crosses the blood-brain barrier and attaches to these receptors directly. This process leads to the psychoactive effects associated with THC. The cannabinoid receptors are not primarily located in areas of the brainstem that control vital functions, such as heart rate and breathing. Therefore, unlike alcohol and opioid drugs that do affect these regions of the brain, even extremely high doses of THC are not believed to result in the significant depression of vital bodily functions, such as respiration or heart rate in the same way that extremely high doses of opiate drugs like heroin and other drugs like alcohol can. Thus, many sources report that it is impossible to suffer a fatal overdose from THC.
  • Therapeutic index: The therapeutic index (also referred to in some sources as the therapeutic window, therapeutic ratio, or safety window) is a comparison of the amount of some specific substance expressed as a ratio that compares the toxic amount to the therapeutic amount or therapeutic effect of the substance. There are some sources that have estimated the therapeutic index for THC to be 40,000:1, meaning that in order to overdose on marijuana (THC), an individual would have to take 40,000 times the normal amount of the drug. As a comparison, the index for morphine is 70:1. Sources citing this index suggest that it is virtually impossible to ingest this amount of THC.
  • Current statistics: A number of resources also report that there are no known recorded fatalities as a result of THC overdose (meaning recorded fatalities as a result of someone only using THC in large amounts). A number of figures from professional organizations, such as the Substance Abuse and Mental Health Services Administration (SAMHSA), are often cited in these sources.

It is true that the majority of the cannabinoid receptors in the brain are not found in areas of the brainstem and that the therapeutic index for THC is extremely high. It is also true that recorded deaths from overdoses on THC are extremely rare; however, it is not true that there are no recorded deaths from suspected THC overdose. The Centers for Disease Control (CDC) issued a report in 2015 of a suspected death from overdose on THC (when ingesting edible cannabis). While some sources will point to possible discrepancies in the report, it does indicate that it is possible, however rare, for individuals to suffer a fatal overdose from THC. The report from the CDC as well as the information listed above indicates that a potentially fatal overdose from THC is probably rare and very unlikely; however, it is a possibility.

It is also important to note that children have demonstrated significant issues with THC overdose when they inadvertently ingest edible cannabis products in states where marijuana has been legalized, and these products are readily available. Edible cannabis products contain high levels of THC compared to regular marijuana.

Increased Marijuana Potency


An important consideration regarding the potential to overdose on marijuana or any other cannabis product is the increased potency of today’s marijuana products compared to the marijuana that was used in the 1960s and 1970s. A recent analysis regarding this issue funded by the National Institute on Drug Abuse compared the potency of marijuana from the 1970s up to 2010. The drug samples were based on marijuana seizures, and the analysis concluded that the average proportion of THC in the marijuana samples was less than 1 percent in the 1970s and had risen to 10-11 percent in the latter 2000s. The rising potency occurred primarily in the late 1980s and 1990s, and it was maintained in the years 2000-2010. Other ingredients in cannabis remained relatively stable in their proportion (e.g., other cannabinoids); therefore, the increased potency in cannabis products is associated with increasing THC levels in the drug.

The figures from organizations, such as SAMHSA, also indicate that there are an increasing number of individuals seeking treatment in emergency rooms for marijuana overdose-related issues, and often, these issues are related to issues with edible forms of marijuana (as is the case with the above fatality) or the use of THC in other methods that increase its delivery and potency significantly, such as the use of “dabs.” Dabs involve more potent and concentrated THC that is extracted from the cannabis plant and then inhaled by using some form of vaporizing method or taken orally. This results in a much quicker action of the drug’s effects and a more intense feeling of euphoria, but it also results in the potential for overdose. Thus, the increased potency of cannabis products and more effective means of administration that are becoming more popular do lead to an increased risk of overdose.

Symptoms of THC Overdose


While it is highly unlikely that an individual will suffer a fatal overdose from marijuana, it is possible to overdose on the drug and experience a number of untoward effects. An overdose on THC is more likely to occur when one uses edible cannabis products or takes THC in some other manner that increases the amount of the substance that one ingests (e.g., using highly concentrated forms of THC). The risks for suffering overdose from THC are increased depending on body weight, tolerance level, and amount and frequency of use. Because THC is fat-soluble, it remains in the system longer, and individuals taking high amounts of THC over lengthy periods of time may not have totally eliminated the drug completely from their system as they ingest more of the drug.

For marijuana, the top indicators of potential overdose include feelings of shakiness or tremors, having an extremely dry mouth, suspiciousness, and visual hallucinations.

Treatment for an overdose of THC depends on a number of different factors, including the individual’s age and body weight. Generally, individuals who overdose on THC will gradually experience a reversal of their symptoms within several hours. However, individuals who have severe THC toxicity or overdose may require:

  • Intravenous fluids
  • Medications for anxiety
  • Medications to control heart rate or blood pressure
  • Isolation and a decrease of environmental stimulation
  • Observation by trained medical personal



It is extremely difficult to overdose on marijuana, especially when an individual is smoking marijuana; one could estimate based on the therapeutic index that an individual would have to take well over 100,000 puffs in a single setting to reach a toxic level of THC in their system. However, despite what a number of sources claim, it is not impossible to overdose on THC. The increased potency of many cannabis products and the increased number of edible cannabis products result in an increased risk that some individuals may experience THC overdose. In addition, certain groups of individuals, such as children, are at extreme risk for overdose on THC due to the availability of the drug in different forms. The potential for a fatal overdose on marijuana is highly unlikely, but it is not impossible as some sources claim.