The Mucuna pruriens bean has high protein and starch contents, but also contains 3, 4-dihydroxy-L-phenylalanine (L-Dopa), which has pharmaceutical properties, but is toxic when ingested by monogastrics. Experiments were conducted to detoxify Mucuna for monogastrics, and to evaluate its anthelmintic effect in ruminants. Experiment (1a) examined how long it takes to decrease the pH of ensiled Mucuna to ≤ 4.6, the typical minimum pH for ensiled legumes. Crushed beans (6 mm) were ensiled for 0, 3, 7, 21, and 28 days. A pH of 4.5 and an L-Dopa concentration of 1.3% (54% reduction) were recorded after 28 days of ensiling. Experiment (1b) determined the effect of particle size (2, 4, or 6 mm) of ensiled Mucuna on L-Dopa concentration and on fermentation and nutritional characteristics. Ensiling 1- or 6-mm particles reduced the L-Dopa concentration by about 60% while preserving most nutrients. Experiment 2 studied the effects of extraction in solutions of acetic acid (ACD, pH 3) or sodium hydroxide (ALK, pH 11) for 8 hours or sonication (SON) for 5 minutes on the L-Dopa concentration and nutritional composition of finely (1 mm) or coarsely (6 mm) ground Mucuna beans. All extraction methods reduced the L-Dopa concentration of fine particles to safe levels (≤ 0.4%) but increased their neutral detergent fiber (NDF) and starch concentrations and decreased their water-soluble carbohydrate (WSC) and crude protein (CP) concentrations. Extraction methods were less 10 effective at reducing the L-Dopa in coarse particles and had inconsisent effects on their nutritional composition. Experiment 3 evaluated the effect of feeding detoxified Mucuna beans on the performance, behavior, and health of 60 Sprague-Dawley rats randomly assigned to five treatments. Dietary treatments consisted of a commercial rat chow (CON) or diets in which 10% of the rat chow was replaced with either undetoxified Mucuna (MUC), or Mucuna detoxified by ACD or ALK extraction, or ensiling for 28 days (SIL). Compared to CON, Mucuna-based diets gave similar feed intake and weight gain. No behavioral abnormalities were caused by any of the diets in open field analyses on days 3 and 10 but when data for both days was collectively analyzed, all Mucuna-based diets exhibited less locomotion than control rats. The decrease in activity was numerically less in rats fed ACD and SIL diets than in those fed MUC and ALK. Feeding MUC caused splenomegaly and monocytosis, and reduced blood phosphorus concentrations relative to CON, but detoxification of Mucuna prevented these effects. Experiment 4 determined if ingestion of Mucuna beans reduces helminth parasite infestation in lambs. Thirty-six Dorper x Katahdin ram lambs (28.8 ± 5 kg body weight) were randomly allocated to three treatments: a cottonseed meal control diet, a diet in which Mucuna replaced cottonseed meal, and a treatment that involved administering levamisole (2 ml/45.4 kg) to lambs fed the control diet. Diets were formulated to be isonitrogenous (14% CP) and isocaloric (64% total digestible nutrients). Lambs were challenged 3 times per week for 2 weeks by gavage with infectious H. contortus larvae. Unlike levamisole treatment, Mucuna intake did not affect (P < 0.05) fecal egg counts (412 vs. 445 eggs/g) or abomasal worm counts (958 vs. 1170 total worms), though a numerical (P > 0.10) reduction was evident. Neither levamisole nor Mucuna treatment affected anemia indicators, daily feed intake, weight gain or dressing. In conclusion, Mucuna intake did not reduce helminth parasite infection in lambs.