Methamphetamine does in fact have natural roots. Both ephedrine and pseudoephedrine are naturally occuring alkaloids of the ephedra plant. You may also be interested to know that reacting lye (sodium hydroxide) with muriatic acid (hydrochloric acid) in the correct ratios will produce table salt (sodium chloride) and water.

Some of the chemicals used in the synthesis of LSD are also extremely dangerous. The natural precursors to LSD come from a very toxic source, the ergot fungus. The alkaloids it contains constrict arteries and blood vessels, leading to gangrene. This fungus grows on rye and interestingly enough may be implicated in the Salem Witch Trials, it likely grew on the stale bread they ate causing hallucinations, delusions and death.