The study comprises some wonderful aspects of the amino acids in medicine. When appended with a suitable linker and an appropriate scaffold, the amino acids, being acceptable to most of the biological systems, unleash numerous activities which could be exploited for the advantage of the mankind. Small amino acid based molecules with potent antimicrobial and antiallergic properties have been identified and quantified. In this book, a small drop from the ocean of the peptide world has been discussed.