As I already stated, LSD is a harmful drug. Unlike some drugs, if LSD is taken it can be tracked down in the body even after a few days, weeks, months, or years have passed. It never leaves your system. If this drug is taken, flashbacks will occur randomly (usually during stressful periods of your life). Even if a person hasn't used the drugs in years, or only used it once, they will encounter these flashbacks.
The effects of LSD are unpredictable because it depends on how much you take, the user's mood when they are taking it, and the surroundings it is being take in. Generally though, heart rate and blood pressure will increase, there will be a loss of apetite, huge mood swings will occur, and the user will see images and sounds that aren't actually there.
http://www.nida.nih.gov/Infofacts/hallucinogens.html
talked a little more about LSD^

<--LSD