An enquiry was carried out in Zaire among workers handling different woods. The aim of the investigation was to establish which woods provoke undesirable reactions of the skin and mucous membranes. Besides the well known toxic woods, 6 types of wood were identified, which had not been known to be cause of these reactions: --Autranella congolensis (dermatitis; ocular and respiratory manifestations); --Drypetes gossweileri (dermatitis; ocular and respiratory manifestations); --Ceiba pentandra (essentially pruriginous manifestations); --Diba di Nzambi (common name) and Ficus capensis (bullous dermatitis); --Combretodendron macrocarpum (dermatitis; ocular and respiratory manifestations).