Erroneous radiocarbon dates on bone collagen may result from impurities remaining after sample processing. Amino acid analysis and a determination of the N-to-C ratio can quickly test the purity of the extracted collagen to indicate if further purifying is required. Collagen is separated from bone by dialysis in diluted HC1 and in distilled water. The collagen is then con-verted to gelatin. The presence of noncollagen organic materials in fossil and modern bones is indicated. When these materials are indigenous to the bone and not contaminants, they do not affect the radiocarbon dates. Radiocarbon dates on noncollagen material extracted from fossil bone should be interpreted with caution. See also AATA 16-1172.