Making appropriate recommendations for safe drinking behavior among different age groups requires understanding of differences between young and older adults in following them. The purpose of this study was to investigate how drinking behavior in terms of drinking speed and bolus size differs between young and older adults following instructions to change drinking rate. Thirty young (mean age 24.7 years) and 30 older (mean age 66.9 years) healthy female participants were recruited. All participants drank water under different drinking instructions: "as they normally would", "as quickly as is comfortably possible", and "slowly". Results showed that when asked to drink quickly, both age groups increased drinking speed to a similar extent. When asked to drink slowly, older adults were unable to slow their drinking rate as much as young adults (P < .001). When drinking slowly, older adults had significantly larger bolus size than young adults'. These suggest that in a healthcare setting, the often prescribed advice to "drinking slowly" may be insufficient precaution for older patients. Prudence is suggested to carefully observe patients drinking after they've been asked to drink slowly, before making a clinical judgment if additional, more specific strategies may be indicated.