The objective of this double-blind, placebo-controlled, dose-escalation study is to evaluate safety, tolerability, and enhancement on healing of thymosin beta-4 (Tbeta-4) administered topically in patients with venous ulcers. Three groups of patients, coming from 10 sites, 5 from Italy and 5 from Poland, will be enrolled sequentially. Twenty-four patients within each group will be randomized to Tbeta-4 or placebo in a 3:1 ratio and will be treated with increasing doses of Tbeta-4. When review safety data show no-dose-limiting adverse events, a new group will be enrolled. So, the study design comprehends 72 patients treated for 84 days and followed for 14 days at the end of treatment. Blood samples will be taken on day 0 and at the end of treatment visit to measure plasma levels of Tbeta-4. Every week each patient is visited and blood samples are taken for clinical chemistry, hematology, coagulation, and urinalysis. Each ulcer is treated with debridement, if necessary, and compression therapy with standard compression stockings class 2. Efficacy parameters are incidence of healing defined as the percentage of patients who have complete closure of the index ulcer at day 84 and, mean time to complete healing. Ulcer area will be calculated by digital planimetry and photographic analysis. The study is ongoing and a total of 21 patients have been enrolled so far in the first treatment group at the lower dose. Patients' compliance and motivated and well-trained teams seem to be the most suitable parameters of a successfully conducted study.