Teething does not cause fever, and blaming it can mask real illness

Teething does not cause a fever. The best evidence — a meta-analysis of 16 studies and a cohort study that measured infants' temperatures every day — finds that erupting teeth are associated with mild local symptoms such as gum irritation, drooling and fussiness, and at most a small rise in body temperature that does not reach the threshold for fever [s1] [s2]. That distinction matters, because attributing a genuine fever to teething can delay attention to an illness that has nothing to do with teeth.

What tooth eruption actually does

A 2016 meta-analysis in Pediatrics pooled 16 observational studies of children aged 0 to 36 months to catalogue what really accompanies primary tooth eruption [s1]. Across a total sample of 3,506 children, the overall prevalence of signs and symptoms occurring during eruption was 70.5% [s1]. The most frequent were local and mild: gingival irritation (86.81%), irritability (68.19%), and drooling (55.72%) [s1].

On the specific question of temperature, the review is careful and clear. It concluded that eruption "could lead to a rise in temperature, but it was not characterized as fever" [s1]. In other words, teething may nudge a baby's temperature slightly, but that nudge is not the same thing as a fever — the elevated, sustained temperature that signals the body fighting an infection.

The study that measured temperature every day

The most rigorous test of the fever claim came from an Australian cohort study that removed the guesswork of parental recall. Researchers followed 21 children aged 6 to 24 months in daycare, taking daily temperature readings and examining their gums each day for erupting teeth [s2]. This produced 236 "toothdays" — the five days before a tooth appeared — and 895 "non-toothdays," across 90 teeth [s2].

Temperatures were essentially the same whether or not a tooth was erupting: a mean of 36.21°C on toothdays versus 36.18°C on non-toothdays [s2]. After adjusting for age, there was no significant association between tooth eruption and high fever (odds ratio, 1.35; 95% CI, 0.80 to 2.27) or low fever (OR, 1.34; 95% CI, 0.48 to 3.77) [s2]. Of a long list of symptoms tested — mood, wellness, drooling, sleep, diarrhoea, rashes — only parent-reported loose stools reached significance (OR, 1.86; 95% CI, 1.26 to 2.73), and even that single association disappeared when the researchers varied the definition of a "toothday" [s2].

The study's most telling finding was social, not clinical: every parent, asked afterwards, retrospectively reported that their own child had suffered a range of teething symptoms [s2]. The belief was universal; the daily data did not support it.

Why the belief is so durable

The mismatch between what parents are certain of and what the measurements show has a simple explanation. Teeth erupt on and off across roughly the first two to three years — the same window in which infants, losing the antibodies they received from their mothers and beginning to mix with other children, catch a steady stream of ordinary viral illnesses. Any fever, fussiness, or bad night that happens to coincide with a visible tooth gets filed under "teething." The eruption is visible and memorable; the coincidence is invisible. The cohort study's whole design — comparing days with and without eruption in the same children — exists to strip out exactly that coincidence, and when it did, the fever link vanished [s2].

Why the distinction is not merely academic

The practical stakes run one direction. If teething genuinely caused fevers, dismissing a feverish, teething baby would be reasonable. Because it does not, treating a fever as "just teething" risks overlooking an infection that would otherwise prompt a closer look. The Wake cohort's authors made this point directly, warning that strong beliefs about teething "may preclude optimal management of common patterns of illness and behavior in young children" [s2].

The evidence supports a narrow, useful statement: eruption can bring sore gums, drooling, and irritability, and perhaps a fractional rise in temperature, but a true fever in a baby is a sign to evaluate, not a symptom to attribute to teeth [s1] [s2]. This article is informational and is not medical advice. A fever in an infant or young child — particularly a high or persistent one, or one accompanied by other symptoms — is a reason to seek medical assessment rather than to assume a cause.