Answering your question in the header, for the best of our knowledge, systematic reviews and meta-analyses indicate that LSD does not harm human health. Studies that point out the opposite usually have a poorly elaborated experimental design (and often the researchers involved in these tend to...
First you have to be more descriptive. Was it an inorganic salt in which the anion is cyanide (CN-)? In this case, the only solution is to administer activated charcoal orally and hope that the affected person can recover.