PURPOSE: To obtain a pharmaceutical composition effective for skin diseases such as acne, Darier disease, psoriasis, ichthyosis, eczema, atopic dermatitis and epithelial cancer, immune diseases such as arthritic disease and lupus erythematosus, wounds, ocular sicca syndrome and skin injuries due to solar light.

CONSTITUTION: This pharmaceutical composition contains a compound (salt) of formula I [X is S, O-N(R') (R' is H, a lower alkyl); R is H, COOH or the like], e.g. ethyl 6-[2-(4,4-dimethylthiochroman-6-yl)-ethynyl]nicotinate and a vehicle. The compound of formula II is obtained e.g. by allowing a compound of formula II to react with a compound of formula III, deriving the obtained compound of formula IV into a compound of formula V through several processes, and subsequently allowing the compound of formula V to react with a compound of the formula: X'-A-(CH2)n-B (X' is a halogen; B is H, a protected acid, an alcohol, an aldehyde, a ketone).