Pectin hydrolysis products are produced by the two-stage hydrolysis of a pectin or pectin-containing plant material with pectin-hydrolysing enzymes. Production of pectin hydrolysis products comprises: (a) treatment of a pectin or pectin-containing plant material in aqueous solution or suspension with a pectin-hydrolysing enzyme (A); and (b) treatment of the product with a pectin-hydrolysing enzyme (B). The products obtained contain galacturonides with at least one 4,5-unsaturated galacturonic acid molecule and are esterified with methanol to >;= 20%. An independent claim is also included for a pharmaceutical or dietetic preparation containing the pectin hydrolysis products and a carrier. ACTIVITY : Antibacterial. No data is given. MECHANISM OF ACTION : None given in the source material.