In the Genealogy of Morality, Nietzsche famously wrote that the sick, weak, and diseased are the greatest danger to human excellence, as they tend to undermine our affirmation of life. They do so because we typically respond to them with attitudes of compassion and care, which, Nietzsche alleges, infects us with their misery. A more healthy reaction, Nietzsche holds, would be the protective reaction of nausea, which typically causes fear and rejection. Fear is nausea's strong somatic response to potential damage of contamination; it puts a safe distance between us and the nauseating item. Rejection in nausea is typically achieved by vomiting—an entirely instinctive and violent rejection of perceived harmful items. Nietzsche uses nausea's strong affective force and, as part of his reevaluation of values, urges us to "relearn nausea" by extending its basic physiological function to what he calls "intellectual nausea." In intellectual nausea we react to perceived damaging intellectual and emotional qualities, such as our unhealthy attitudes to the sick and weak, with the same instinctive affective force as we do in basic physiological nausea—that is, by putting a safe distance between ourselves and what is deemed a damage or a threat and by rejecting it.