Acid tabs. Sheets of blotting paper cut into squares (or tabs) and impregnated with LSD (Lysergic Acid Diethylamide, also known as acid). Different brands of LSD are identified by the illustration on each tab. LSD is a psychedelic drug (it changes the level of consciousness) and a hallucinogen. It is commonly used for recreational purposes despite being illegal in most countries. Colourless, odourless and easily synthesized it is non-addictive and non-toxic, but its effects are unpredictable. The drug was first synthesized by a German chemist, Albert Hofmann, in 1943. It was banned in the US in 1965, and in the UK in 1966.