Marijuana smokers may need to reconsider their habit. According to a new study exposure to marijuana smoke can lead to allergic reactions in some people. Marijuana is a pollen-bearing plant which makes it an allergen. Among other things cannabis pollen or cannabis smoke exposure has resulted in symptoms of allergic rhinitis (hay fever) conjunctivitis and asthma said Thad Ocampo from Wilford Hall Ambulatory Surgical Center San Antonio Texas. Read about why marijuana is harmful for teenagers. The researchers have cited case reports regarding episodes of allergic reactions hypersensitivity and even anaphylaxis (a severe allergic reaction) to cannabis in its various