Eyes: Tetrahydrocannabinol (THC), the chemical responsible for the marijuana high, lowers blood pressure, impacting cells in the eyes. Blood vessels in the eyes expand in response to low blood pressure, a normal response to maintain proper vision. Dilated capillaries and open blood vessels increase blood flow, leading to bloodshot eyes. Redness is more visible against the white part of the eye (sclera). The higher the THC content, the greater the likelihood of bloodshot eyes, therefore edibles can also cause this side effect. Marijuana smoke creates additional eye irritation in some people. This can result in itchy, dry and watery eyes in addition to a “bloodshot” appearance. 
Oral health: Marijuana use can lead to several oral problems, most notably chronic dry mouth and an increased risk of cavities. THC is an appetite stimulant, so users tend to get “the munchies” and eat sugar-laden snacks. Irritation, leukoedema (whitish lesions) and erythema (redness) of the oral tissues are other potential side effects. A limited number of studies show a correlation between marijuana use and the risk of periodontal disease. The high intraoral temperature from marijuana smoking can cause changes in oral tissues and cellular disruption and limited studies have shown a link to oral cancers. The immunosuppressive effects of cannabis may contribute to some cancers and a higher prevalence of oral candidiasis (thrush) in users compared to nonusers. While many of these oral side effects are not immediately visible, dry mouth can lead to chronic bad breath. Oral problems are often compounded by co-occurring tobacco, alcohol and other drug use, poor oral hygiene and infrequent visits to dentists. Skin: Marijuana constricts blood vessels prior to dilation, depriving the skin of oxygen, just like cigarette tobacco. The toxic effects can lead to accelerated aging of the skin. When high hydrocarbon levels in marijuana contact the skin, collagen production is compromised. Collagen provides structural strength that protects the skin from air pollution and inflammation. Damage to collagen can prematurely age the skin by causing wrinkles and loss of elasticity. Weight gain: Some studies suggest the THC and cannabidiol (CBD) in marijuana can increase abdominal visceral fat, while others contradict these findings. Conclusive evidence shows THC is an appetite stimulant and helps combat nausea, which is why it is prescribed medically for individuals with physical debilitation and weight loss related to cancer and HIV/AIDS. Current data suggest that in the general population, marijuana use may lead to lower body mass index. Researchers theorize the inverse effect on body mass index may be a result of food and drugs competing for the same reward sites in the brain. The relationship between marijuana use and weight is complex, depending on factors such as duration of use, comorbid polydrug use (including nicotine), dietary intake, gender and age. It appears that some people experience visible weight gain, while others do not. While the effects of marijuana alone generally do not cause fatalities, chronic use can lead to serious health issues. Among the risks are heart palpitations, arrhythmias, heart attack and respiratory problems (e.g., chronic cough, chest illness and lung infections). THC stays in the body a long time, so withdrawal can be drawn out, occurring seven to 10 days after quitting. Marijuana addiction treatment helps users cope with anxiety, drug cravings, irritability, insomnia and changes in appetite associated with withdrawal.
