In patients with lymphedema, reduced lymph drainage capacity results in an overloaded superficial microlymphatic network and microlymphatic hypertension. In in vitro experiments, it has been shown that 8-epi-prostaglandin F2α (PGF) induced contractions in human lymphatics. Since lymphatic contractility plays a crucial role in the regulation and generation of lymph transport, we studied the effect of PGF on microlymphatic dynamics by measuring lymph capillary pressure (LCP). Twenty healthy volunteers and 13 patients with primary lymphedema were studied after either PGF or placebo was applied to the skin and occlusively covered for 30 min. Glass micropipettes (7–9 µm) were inserted under microscopic control into initial lymphatics visualized by fluorescence microlymphography and pressure measurements were performed using the servo-nulling technique. The mean LCP in patients with lymphedema was significantly higher (19.8 ± 12.1 mm Hg) than that in healthy controls (8.4 ± 4.1 mm Hg) at the placebo-treated site and decreased to normal values after PGF (10.0 ± 7.7 mm Hg). In healthy volunteers, there was no significant decrease of LCP with PGF compared to placebo. PGF normalizes microlymphatic hypertension in patients with lymphedema by improving lymph transport into deeper channels.