Slobbers is a type of mycotoxicosis that is associated with ingestion of red clover (Trifolium pratense) contaminated with the fungus Rhizoctonia leguminicola (blackpatch disease). R. leguminicola produces two indolizidine alkaloids: slaframine and swainsonine.

• Slaframine: Slaframine is thought to be primarily responsible for the slobbering, which occurs in a wide range of concentrations, varying from 1.5 ppm to 100 ppm.
• Swainsonine: Swainsonine is known for causing locoism (due to consumption of locoweeds (Astragalus spp and Oxytropis spp)), resulting in neurological problems (e.g., staggering, nervousness, and lack of coordination).

Slobbers is considered somewhat common in horses grazing in pastures in the southeastern United States (US). Outbreaks of slobbers have been documented in horses consuming mixed orchard grass and alfalfa hay and grazing red clover in pastures throughout the midwestern and southeastern US, Brazil, Canada, Japan, and the Netherlands.

The excessive slobbering can last for several hours our several days. The fungus appears in pastures during periods of hot and humid weather, usually late summer. The same fungus also infects white clover (Trifolium repens), alsike clover (Trifolium hybridum), or alfalfa (Medicago sativa). Red clover found in hay can also be affected by the fungus, as R. leguminicola remains on the clover in fresh or dry forms.