Barlican, a β-glucanase enzyme obtained from Trichoderma reesei, was produced by a fermentation process and subjected to a series of toxicological tests to document its safety for use as a feed additive. The enzyme product was examined for general oral toxicity, inhalation toxicity, irritation to eye and skin, skin sensitization and mutagenic potential. An extensive literature search on the production organism was also conducted. Furthermore, safety for target species was assessed in a 28-day oral toxicity study with broilers. A strong skin-sensitizing potential of the β-glucanase enzyme was detected, but no other evidence of oral or inhalation toxicity, mutagenic potential, eye or skin irritancy was found. Feeding of the β-glucanase enzyme at dietary levels up to 10,000 ppm in the 90-day subchronic toxicity study in rats did not induce noticeable signs of toxicity. In addition, no adverse effects were observed when broiler chicks were fed dietary concentrations of the β-glucanase enzyme up to eight times the daily recommended dose. it is therefore concluded that this β-glucanase preparation is safe for use in feed of the intended target species. However, some occupational hearth precautions should be taken to avoid skin contact and inhalation, as is the case for almost all enzyme proteins.