Psilocybin's careful ritual use by native peoples has evolved into college students' recreational mushroom use. This experience is generally viewed as a milder and shorter LSD-like experience. At low doses, psilocybin causes simple feelings of relaxation, physical heaviness or lightness, and some perceptual distortions (especially visual). At higher doses, more physical sensations occur, including lightheadedness, numbness of the tongue, lips, or mouth, shivering, or sweating nausea, and anxiety. There is probably almost as much misinformation about mushrooms as there is about LSD. The most common mushrooms used in the U.S. contain psilocin and psilocybin. Psilocybin is distributed both in dried mushrooms and as white powder. A typical dose is four to ten milligrams, or two to four mushrooms. Hallucinogenic mushrooms present an identification problem. It takes an educated and practiced eye to identify any mushrooms in the field, and this is always a dangerous proposition. Many mushrooms' species contain toxins that are extremely dangerous or lethal. The identity of dried mushrooms can be very difficult to establish.