Not according to modern medical science. According to the U.S. government, of the more than 7,000 chemicals in tobacco smoke, at least 250 are known to be harmful, including hydrogen cyanide, carbon monoxide, and ammonia (1, 2, 5). Among the 250 known harmful chemicals in tobacco smoke, at least 69 can cause cancer.
As for marijuana, according to WebMD:
"Oct. 17, 2005 -- Although tobacco smoke and marijuana smoke are chemically very similar, a new report argues that their cancer-causing effects may be very different.
Both tobacco and cannabis smoke contain the same cancer-causing compounds (carcinogens). Depending on what part of the plant is smoked, marijuana can contain more of these harmful ingredients.
But a recent review of studies on the effects of marijuana and tobacco smoke suggests that the cancer-promoting effects of these ingredients is increased by the tobacco in nicotine and reduced by the tetrahydrocannabinol (THC) found in cannabis.
Previous studies have shown that THC can inhibit carcinogens in mice, and the report suggests it may have the same protective effect against the carcinogens found in smoke in humans. But researchers warn that even if THC lessens the effects of these cancer-causing ingredients, cannabis smoke remains carcinogenic."
Best not to smoke 'em if ya got 'em.