Deethylindanomycin is a polyether antibiotic that has been found in S. setonii. It is active against a variety of Gram-positive bacteria, including various strains of S. aureus and Streptococcus, as well as one strain of S. pneumoniae (MICs = 4, 4, and 2 µg/ml, respectively). It is also active against coccidia in vitro, inhibiting E. tenella development, but is inactive against E. tenella infection in chicks when administered at a dose of 200 µg/g in the diet. Deethylindanomycin acts as an ionophore in lipid bilayer membranes and is more selective for potassium ions than calcium, magnesium, and sodium ions. It induces histamine release from rodent mast cells and human basophils in vitro in a calcium-dependent manner.