Medicinal plants are abundant in the Brazilian flora including the Cerrado region. Extracts of sixteen plant species of the Brazilian Cerrado were investigated in vitro for antiviral activity against bovine herpesviruses type 1 (BoHV-1), infectious bursal disease virus (IBDV) and avian reovirus. Eight plants presented potent antiviral activity. Erythroxylum deciduum, Lacistema hasslerianum and Xylopia aromatica against BoHV-1; Gochnatia polymorpha and Lithraea molleoides against avian reovirus; and Banisteriopsis variabilis, Byrsonima intermedia and Campomanesia xanthocarpa against both viruses. No extract was active against IBDV.