Edible forms of cannabis often contain several hundred milligrams of THC per dose, much more than the 32mg of a typical cannabis cigarette
According to the Merck Index, the LD50 of THC (the dose which causes the death of 50% of individuals) is 1270 mg/kg for male rats and 730 mg/kg for female rats from oral consumption in sesame oil, and 42 mg/kg for rats from inhalation.It is important though to note that cannabinoids and other molecules present in cannabis can alter the metabolism of other drugs, especially due to competition for clearing metabolic pathways such as cytochromes CYP450, thus leading to drug toxicities by medications that the person consuming cannabis may be taking. Related to smoking
A 2007 study found that while tobacco and cannabis smoke are quite similar, cannabis smoke contained higher amounts of ammonia, hydrogen cyanide, and nitrogen oxides, but lower levels of carcinogenic polycyclic aromatic hydrocarbons (PAHs). This study found that directly inhaled cannabis smoke contained as much as 20 times as much ammonia and 5 times as much hydrogen cyanide as tobacco smoke and compared the properties of both mainstream and sidestream (smoke emitted from a smouldering joint or cone) smoke. Mainstream cannabis smoke was found to contain higher concentrations of selected polycyclic aromatic hydrocarbons (PAHs) than sidestream tobacco smoke. However, other studies have found much lower disparities in ammonia and hydrogen cyanide between cannabis and tobacco, and that some other constituents (such as polonium-210, lead, arsenic, nicotine, and tobacco-specific nitrosamines) are either lower or non-existent in cannabis smoke.
Some users may store marijuana in an airtight bag or jar in a refrigerator to prevent fungal and bacterial growth. Fungi
The fungi Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus parasiticus, Aspergillus tamarii, Aspergillus sulphureus, Aspergillus repens, Mucor hiemalis (not a human pathogen), Penicillium chrysogenum, Penicillium italicum and Rhizopus nigricans have been found in moldy cannabis. Aspergillus mold species can infect the lungs via smoking or handling of infected cannabis and cause opportunistic and sometimes deadly aspergillosis. Some of the microorganisms found create aflatoxins, which are toxic and carcinogenic. Researchers suggest that moldy cannabis should thus be discarded to avoid these serious risks.Mold is also found in smoke from mold-infected cannabis, and the lungs and nasal passages are a major means of contracting fungal infections. Levitz and Diamond (1991) suggested baking marijuana in home ovens at 150 °C [302 °F], for five minutes before smoking. Oven treatment killed conidia of A. fumigatus, A. flavus and A. niger, and did not degrade the active component of marijuana, tetrahydrocannabinol (THC)." Bacteria
Cannabis contaminated with Salmonella muenchen was positively correlated with dozens of cases of salmonellosis in 1981. "Thermophilic actinomycetes" were also found in cannabis. Long-term effects
Exposure to marijuana may have biologically based physical, mental, behavioral, and social health consequences and is "associated with diseases of the liver (particularly with co-existing hepatitis C), lungs, heart, eyesight, and vasculature" according to a 2013 literature review by Gordon and colleagues. The association with these diseases has only been reported in cases where people have smoked cannabis.