Procaine is a benzoate ester, formally the result of esterification of 4-aminobenzoic acid with 2-diethylaminoethanol but formed experimentally by reaction of ethyl 4-aminobenzoate with 2-diethylaminoethanol. It has a role as a local anaesthetic, a central nervous system depressant, a peripheral nervous system drug and a drug allergen. It is a benzoate ester, a substituted aniline and a tertiary amino compound. It is functionally related to a 2-diethylaminoethanol and a 4-aminobenzoic acid. It is a conjugate base of a procaine(1+).