Long a tradition in China, the hottest summer days are used to cure and prevent winter illness. Marking the year's warmest weeks, the period known in China as sanfu is considered an ideal time to boost your health. This year san fu began with chufu on July 17, has zhongfu as its mid-point on July 27 and its final period mofu begins on August 16 and ends on August 25.

In the lead up to today's chufu, hospitals have been busy dealing with crowds of people eager to buy and apply a herbal plaster (futie) to prevent winter illness.

It is said that human beings and nature are united and that humans should adjust their daily lives including diet, sleep and mindset according to different characteristics of the four seasons in order to achieve a yin-yang balance of the body.

With the cold weather in winter, the human body tends to contain excessive yin energy due to insufficient yang energy, which makes people liable to attract diseases such as bronchitis, rheumatism, bronchial asthma and cold in the spleen and stomach.

Treating winter ailments in summer means that summer, a season when yang energy peaks, is the time to nourish yang energy for winter, thus relieving and preventing those chronic cold-related ailments that plague people during the chillier months.

The key components of the healing herbal plaster varies from hospital to hospital, but most include traditional Chinese herbal medicines which are deemed helpful to nourish yang energy such as storax, musk, bulbus fritillariae and Chinese caterpillar fungus.

Due to the different formulas of each hospital, the time of applying the plaster is also not the same. Some hospitals state that their plaster should be applied on the first day of each sanfu period while other hospitals say that any day within the entire time is fine.

The herbal plaster is applied on specific acupuncture points of body according to the corresponding part that is in need of care.

Dating back to the Qing Dynasty (1644-1911), the application of herbal plasters continues to be viewed as a very effective way to relieve and prevent winter ailments.