The present invention relates to selected (R)-2-phenyl-propionamides and (R)-2-phenyl-sulfonamides with a hydrogen bond acceptor atom/group in a well defined position in the chemical space. These compounds show a surprising potent inhibitory effect on C5a induced human PMN chemotaxis. The compounds of the invention absolutely lack of CXCL8 inhibitory activity. Said compounds are useful in the treatment of pathologies depending on the chemotactic activation of neutrophils and monocytes induced by the fraction C5a of the complement. In particular, the compounds of the invention are useful in the treatment of sepsis, psoriasis, rheumatoid arthritis, ulcerative colitis, acute respiratory distress syndrome, idiopathic fibrosis, glomerulonephritis and in the prevention and treatment of injury caused by ischemia and reperfusion.