Hair-growing composition

A method of growing hair on an animal, including a human, comprising:

• administering to said animal a 5,6,7-trinor-4,8-inter-m-phenylene prostaglandin I.sub.2 derivative of the formula (I) below or a pharmaceutically acceptable salt thereof, in an amount effective for stimulating the hair growth of said animal;
• ##STR3## wherein R.sup.1 represents hydrogen, a carboxylic group or a functional derivative thereof, --CH.sub.2 OH or a pharmaceutically acceptable cation;
• A represents
• (i) --(CH.sub.2).sub.n --,
• (ii) --(CH.sub.2).sub.m --C.dbd.CH--(CH.sub.2).sub.p --,
• (iii) --(CH.sub.2).sub.m --C.tbd.C--(CH.sub.2).sub.p -- or
• (iv) --CH.sub.2 --O--CH.sub.2 --
• wherein n represents an integer of 0-3, m and p, the same or different, represent 0 or 1;
• R.sup.2 represents
• (i) C.sub.5 -C.sub.10 straight or branched alkyl group,
• (ii) --C.sub.t H.sub.2t --OR.sup.3, wherein t represents an integer of 1-5, R.sup.3 represents a C.sub.1 -C.sub.5 straight or branched alkyl group or a phenyl group,
• (iii) --C.sub.t H.sub.2t --CH.dbd.C(R.sup.4)(R.sup.5)
• wherein t has the same meaning as mentioned above, R.sup.4 and R.sup.5, the same or different, represent hydrogen, methyl, ethyl, propyl or a butyl group, or
• (iv) --C.sub.t H.sub.2t --C.tbd.C--R.sup.6
• wherein t has the same meaning as mentioned above, R.sup.6 represents hydrogen, methyl or an ethyl group, and --C.sub.t H.sub.2t in (ii), (iii) and (iv) represent a straight or branched alkylene group;
• and
• wherein said compound of formula (I) may be in a d-, 1- or dl-form.