There is a growing population who suffer from hyposalivation. These patients frequently sip liquids to alleviate their discomfort. Milk appears to have many of the physical properties of a good saliva substitute. Desalivated rats given 2% milk or lactose-reduced milk remained essentially caries-free. In contrast, animals given sucrose or lactose to drink developed caries. In addition, animals given sucrose or lactose harbored significantly higher populations of Streptococcus sobrinus than did other groups. Results showed that milk and lactose-reduced milk can be used safely by hyposalivatory patients as a saliva substitute.