Menopause symptoms can be considered a disability and employers face being sued if they do not make "reasonable adjustments", a watchdog has said.
The Equality and Human Rights Commission (EHRC) issued the guidance to clarify the legal obligations to workers going through the menopause.
Symptoms can include hot flushes, brain fog and difficulty sleeping.
The EHRC said bosses should offer changes such as providing rest areas or flexible hours to help.
Relaxing uniform policies to allow women to wear cooler clothes could also help.
Menopause marks the end of a woman's menstrual cycle, and usually happens in her 40s or 50s.
Failing to make "reasonable adjustments" amounts to disability discrimination under the Equality Act 2010 if the symptoms have a "long-term and substantial impact" on a woman's ability to carry out their usual day-to-day activities, the EHRC said.