This is true, but where a typical smoker inhales 20 grams of plant matter per day or so, a typical pot smoker will inhale far less than that. There's not research that suggests that smoking a couple of joints a week will harm your health Alcohol is one of the more dangerous drugs and unlike weed a (delicious) scourge to society. This is even more true for pot. The amount of carcinogens in marijuana depends on which part of the plant you use. There are parts of the plant with 70-100% more carcinogenic chemicals in it than tobacco, and contain very low amounts of THC. (THC is likely to inhibit carcinogens). There are also parts with equal or lesser quantities of carcinogens compared to tobacco, and moderate amounts of THC. What also should be noted, is that all toxins are toxic based on exposure and potency. Most carcinogens in both tobacco and marijuana are not too potent, but there are a few in both that are very potent. Most carcinogens also take decades between when they start to effect a person, and when cancer shows up. Drinking alcohol affects the body differently than smoking marijuana and tobacco. Alcohol damages the body mainly because you drink more than your liver can process. The liver is very important to body function, but very resilient, and can stand up to even severe damage from alcoholics for years, and when a person drinks an amount their liver can handle, almost no damage is accrued. Marijuana and tobacco are normally taken orally through inhalation, and will go directly to the lungs, and will enter the blood very quickly. The lungs can and normally will be damaged when any abnormal substance enters them, as they aren't meant to deal with large particles. The carcinogens in either substance are likely to affect the body while in the lungs. This is where the two products act differently. Nicotine in tobacco changes how the heart, muscles, and brain behave (All potentially deadly). The THC and CBD in marijuana do most of their work in the brain. None of the direct affects are lethal, but THC and CBD by themselves are both deadly in relatively small doses when they enter the blood. Most medicinal marijuana growers and producers of THC pills make the mistake of thinking THC is fine to isolate since it is the cannabiniod that helps more, but CBD has been proven to counteract the deadly affects of THC, and it has been proven that THC counteracts the deadly affects of CBD. Neither one helps deal with the carcinogens, and other cannabinoids, but the fact that growers isolate THC makes THC poisoning more likely. This isn't saying that the two cannabinoids shouldn't be used medicinally, just that they shouldn't be used by themselves, or with the other chemicals present in marijuana. There is no way a grower can get just these two chemicals in precise amounts. Just burning the leaves of most plants will produce enough carcinogens to be deadly, so smoking anything at all is just not wise, and I am in no way ever going to support the smoking of any plant. That said, there is no way you can moderate marijuana or tobacco to keep yourself healthy. The carcinogens and other chemicals will damage your body, no matter what, every time you use them, raising your risk for infections. You could potentially get cancer from one use of either substance, too. I didn't want to sound mean or rude in any way, and I spent two hours writing this to try to avoid offending you. If I did, please inform me. My goal is never to offend, but it is always to learn, teach, and discuss. Most drugs, medical and recreational, were derived from plants or bacteria, and synthetics were made to make them safer. Smoking, ingesting, or injecting almost any plant or bacteria that can alter the body is dangerous, and burning it only creates carcinogens. I do think most plants are beautiful, though, and the uniformity of cannabis is amazing to me. If I lived somewhere it grows naturally, I would most certainly not remove it, risking damage to the ecosystem, and damage to the aesthetics of the area.