Relatively little is known concerning Al toxicity in man or animals. Current literature associates encephalopathy, osteodystrophy, and anemia with excessive Al accumulation. The normal gastrointestinal tract is probably an efficient barrier to absorption and the normal kidney appears to eliminate Al efficiently. When administered parenterally, the g.i. barrier is by-passed. In the presence of renal failure, accumulation may occur. "Toxic" levels of Al have not been clearly established to guide clinicians, nor have "safe" levels in parenterals been defined. The extent of intoxication as a clinical problem is unknown, but may be more common in selected patient groups than is recognized. In the absence of reliable data, specific regulatory action has not been taken. In the interest of public health, the FDA is attempting to accumulate information for guidance of parenteral drug manufacturers and clinical practitioners.