Is smoking weed occasionally too harmful.to health ? and can weed b adulterated ?

Marijuana is an Herb: Yes and no. Marijuana is very well known to not have many if any real negative health effects. But, daily or obsessive use can really dull one's human experience and lead to other addictive diseases or behaviors. The jury is out on the damage the 'fire' in smoking can cause. It is well documented in nicotine smoking. The anti-inflammatory properties of mj may protect some against the smoke damag.