A discussion of a case decided by the Court of Appeals for the Federal Circuit, the highest specialized court of appeal for intellectual property, which raises the standards for obtaining patent protection for biological compositions. The decision in Enzo Biochem, Inc. v. Gen-Probe Inc., No. 01-1230, decided April 2, 2002, has broad implications for biotechnology companies seeking to protect (and possibly enforce) their discoveries. Enzo points out that if a written description contained in a patent is absent, vague, or otherwise unclear, it greatly complicates prosecution of the patent application, and also provides several points of attack against the validity of the issued patent.