This invention relates to bioadhesive compositions, which are particularly, but not exclusively, useful for making medical electrodes and to medical electrodes based on such compositions. A first bioadhesive composition comprises: 10 (i) 28-60 wt % of a copolymer comprising repeating units derived from one or more monomers selected from olefinically unsaturated sulphonic acids and repeating units derived from one or more olefinically unsaturated carboxylic acids, the ratio by weight of the sulphonic acid units to the carboxylic acid units being from 30:1 to 1:1; 15 (b).