Anti-inflammatory properties of Populus tremula are mainly deduced from its components, the well investigated salicylates. Solidago extracts have spasmolytic, antihypertensive and diuretic effects. Fraxinus excelsior itself has hardly been investigated, but its coumarin components proved to have a variety of pharmacological properties, i.e. inhibition of T-cell activation and of the arachidonic acid cascade. Phytodolor N (abbreviated as PD) is a combination of the above mentioned plants. Various in vitro and especially in vivo studies proved its anti-inflammatory and antirheumatic properties, often comparable to non-steroidal anti-inflammatories, but with little or no side effects.