Bloat
Black medic can cause bloat if over-consumed (MSUE, 2017).
Flavonoids, saponins and phenolics
Aerial parts of black medic contain flavonoids, saponins and phenolics with hemolytic and antinutritional activities for monogastric animals (Gorski et al., 1984; Burda et al., 1988; Kicel et al., 2015). Flavonoids and saponins contents are particularly high (3.5% DM) in the top parts and seeds (Gorski et al., 1984). Saponins content is at least twice higher in very young germinated seeds (Gorski et al., 1984). Total phenolic content is also high with 162.4 g/kg DM (Kicel et al., 2015).
Coumestrol
Like alfalfa and other legumes, black medic contains relatively high coumestrol content (32 mg/kg DM) which is known to have estrogenic activity (Taujenis et al., 2016). Because of the flavonoid and coumestrol contents it is recommended to limit the access of pure black medic culture to ruminant females, particularly around the reproduction period and during pregnancy (Taujenis et al., 2016). The same cautions applying for alfalfa can be addressed to black medic.