Nothing in this world is perfectly safe. Even drinking too much water can kill you. Even water comes with a long list of potential side effects. You should never base a medical decision only on the existence of a list of side effects. As should be obvious at this point, you can't label some substances as always safe, and other substances as always dangerous. The situation is more complicated than that. In general, there are several factors that determine the risk that a substance can harm a person: 1. The toxicity of the substance, 2. The dose of the substance and 3. The person's unique sensitivity to the substance and their health situation.....