Bufalin (BF) is a potent inhibitor of steroid receptor coactivator SRC-3, SRC-1 and Na+/K+-ATPase. Bufalin binds to the subunit α1, α2 and α3 of Na+/K+-ATPase with Kd of 42.5 nM, 45 nM and 40 nM, respectively. Bufalin is a major digoxin-like immunoreactive component isolated from the Chinese medicine Chan Su with anti-cancer activity.