SALT OF OPTICALLY ACTIVE SULFOXIDE DERIVATIVE

PROBLEM TO BE SOLVED: To obtain a new compound, having an antagonistic activity for receptors of both substance P and neurokinin A and useful as prophylactic and therapeutic agents for tachykinin-mediated diseases. SOLUTION: This compound is a hydrochloride or a fumarate of 1- 2-[(2 R)-(3,4-dichlorophenyl)-4-(3,4,5-trimethoxybenzoyl)morpholin-2-yl]ethy l}spiro-[benzo(c)thiophene-1(3H),4'-piperidine]-(2S)-oxide [a compound represented by the formula (>S* → O is a sulfoxide in which oxygen is combined with sulfur by the absolute configuration)]. The compound can be produced by converting the compound represented by the formula into the hydrochloride or the fumarate according to a well-known method. For example, psychosis, Alzheimer's disease, osteoarthritis, inflammatory intestinal disease, bronchitis, asthma, rhinitis, incontinence of urine and collagen disease are cited as tachykinin-mediated diseases.