The aim of this study was to investigate vegetative reactions in infants after mechanical irritation of the suboccipital region. The investigation is based on 199 infants who were observed while being treated with a suboccipital impulse (manual therapy). The results revealed vegetative reactions in more than half of all cases (52.8%, n = 105). The frequency of such vegetative reactions observed was at follows: flush 48.7% (n = 97), apnoea 22.1% (n = 44), hyperextension 13% (n = 26), and sweating 7.5% (n = 15). It is pointed out that approximately 25% of all the infants examined reacted by apnoea due to a mechanical irritation of the suboccipital region. This symptom was part of an extensive vegetative reaction. This method of inducing an apnoea has not yet been described; from this it follows that there are close relations to sudden infant death.