Sleep is as essential to our bodies as eating, drinking, and breathing. This month, neuroscientist Rachel Williams returns to host a sleepy tea making session at the Book Club in London exploring the history of sleep-inducing herbs and medicine. She tells us how we might add zzzs to our bedtime…

Herbs have been integral to both traditional and non-traditional forms of medicine, dating back at least 5000 years. Our ancestors smelt them, tasted them, and systematically figured out what worked for the people in their communities. Over 70% of the UK population get their daily herbal fix through a cup of tea, and there’s a huge variety of sleepy teas on the market. The question is – how much did our ancestors get right? And how much can we learn about modern sleep aids from humanity’s herbal history?

The herbs we drink


Over a million cups of camomile tea are consumed each day worldwide.  The tea is made from extracts of dried camomile flower, which contain many chemical compounds including benzodiazepines – drugs used as mild tranquillisers. These compounds can inhibit brain activity and might be responsible for camomile’s potential sedative properties.

Keefe et al. (2016) showed that intake of camomile daily over 2 months led to a reduction of anxiety symptoms. However, participants in this research study were given a very high concentration of pharmaceutical-grade camomile, and so the effect was much larger than any potential relaxing effect from drinking a cup of tea.

Lemon balm

Lemon balm has been used as a herbal medicine as far back as the Dark Ages to reduce stress and promote sleep. In the Middle Ages, lemon balm was also steeped in wine to lift the spirits, heal wounds, and treat venomous insect bites and stings. Essential oils made from lemon balm leaves contain plant chemicals called terpenes, which play a role in the herb’s relaxing and antiviral effects.

Several scientific studies show that lemon balm combined with other calming herbs (such as valerian, hops, and camomile) may help to reduce anxiety and promote sleep. However, the research doesn’t look at a large enough portion of the population or examine the effectiveness of lemon balm on its own – so the results are not yet conclusive.

Terpenes are also responsible for the aroma of cannabis, but the sedative effects of the drug are caused by a chemical called THC. Unfortunately, THC has been shown to increase as well as decrease feelings of anxiety – the grass isn’t always greener…

From opium to morphine

There’s one plant we know for sure will knock you out, and that’s opium. The Ancient Greek god of sleep, Hypnos, is often shown carrying an opium poppy in paintings. In fact, the Greeks weren’t the first to notice the potency of the plant – it was introduced to them by the Ancient Egyptians who used it for ritual purposes.

It’s no wonder that a plant with a reputation spanning a few millennia was put to use as a sleep aid across the globe during the 19th century. Morphine, derived from opium, was one of a number of new synthetic chemical compounds that we used to alter states of consciousness as an anaesthetic, pain reliever, and to induce sleep. Morphine is still used by doctors to relieve pain – though only in extreme cases such as during invasive operations or after heart attacks.

Sleep drugs – melatonin agonists

A group of modern drugs called melatonin agonists are much more advanced compared to sleep aids of the past. Melatonin is a natural hormone made in the brain that controls how asleep or awake you feel. During the course of a day, daylight prevents the production of melatonin and keeps you awake but, as we enter the dark of the evening, melatonin is produced and increases feelings of sleepiness. Melatonin agonists mimic the actions of the hormone and make people tired using the brain’s own in-built mechanism. These drugs are much safer than morphine, because they don’t cause withdrawal effects or dependence.

The psychology of sleep – tea as a placebo and comforter

The jury is still out on whether herbal tea can physically induce sleep. Scientists need to find evidence that the chemicals from these herbs are absorbed by the digestive system, transported in the bloodstream, and pass the highly selective barrier that allows molecules in the blood to enter the brain. Lastly, we need to be able to prove that it is the action of these chemicals in the brain that causes drowsiness. Long story short, there’s a lot of work to be done!

But this doesn’t mean that tea has no effect. Rather, the psychological experience of drinking tea alone or with friends can be relaxing – many of us know the happiness that a chat with friends over a cuppa can bring. Cultures around the world have developed rituals or habits involving tea-drinking that in themselves reduce stress, whether it’s slowly savouring the flavours or an unspoken agreement to have a 3pm tea break in the office.

Today psychological treatments and talking therapies, such as cognitive behavioural therapy, are being recommended to empower patients to take control of their sleep. Top tips for improving your sleep hygiene include switching off electronic devices before you get into bed, sticking to a regular sleep schedule, and doing something relaxing before bedtime.


Tickets for Lessons in Lucid Dreaming featuring Rachel’s sleepy tea workshop are now available here!