The compounds are substituted thioalkyl , aminoalkyl and oxyalkyl guanidines which are {TAIL ~ inhibitors} of {HEAD ~ histamine activity} 
The compounds are substituted thioalkyl , aminoalkyl and oxyalkyl guanidines which are { TAIL ~ inhibitors } of { HEAD ~ histamine activity }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD