Transcript: What are the drawbacks of smoking cannabis? The drawback is the smoke. Cannabis & tobacco smoke have a similar range of harmful bronchia irritants & carcinogens. Drawing smoke through a water pipe removes gas-phase smoke toxins such as ammonia, carbon monoxide, acetaldehyde, and nitrosamines. Particulate-phase toxins such as polycyclic aromatic hydrocarbons are NOT REMOVED. Polycyclic aromatic hydrocarbon is also known as “tar”. Tar is one of the main culprits that causes lung cancer. Consume responsibly. Consult with a cannabis specialist at WeedRecs.