An investigation was conducted into the effects of two phenolic amines, N -methyl-β-phenethylamine (NMP) and tyramine (T) on corpus luteum function and reproductive performance of Angora goats. Both compounds are widely distributed through the plant kingdom and, because of their sympathomimetic action, may interfere with normal reproductive processes. In Experiment I, 20 nannies (x = 26.7 ± 0.96 kg) received either 0, 1, 2, or 4 mg NMP in 2 ml com oil/kg BW daily, for 45 days. In Experiment 2, 75 nannies (x = 32.1 ± 0.46 kg) received either 3, or 6 mg/kg BW NMP in 2 ml corn oil; 1, or 3 mg/kg BW T in physiological saline, or 2 ml corn oil (control) daily, for 45 days. In both studies treatments were administered by i.v. injection. Mating was by natural service, beginning after the start of treatment. Jugular blood samples were collected weekly, processed to yield serum, and serum progesterone (P4) concentrations were determined by radioimmunoassay (RIA). In Experiment I, no dose response was detected but P4 concentrations were reduced (P = 0.03) in the treated animals. In Experiment 2, no dose response was detected but P4 concentrations in NMP-treated animals (3.87 ± 0.618) were lower (P = 0.05) than in the control (5.65 ± 0.747) or in T-treated animals (4.73 ± 0.528, P = 0.08). No difference in P4 concentrations was detected between T-treated and control animals (P = 0.59). Fewer NMP-treated nannies became pregnant (59%) than either control (77%) or T-treated nannies (88%) (P = 0.053). The results show that exogenous phenolic amines vary in their effect on reproductive performance of nannies.