This tiny malevolent creature is believed to have caused human illness during the 16th century in Japan.
Kakuran no Mushi is a worm with a black head and red body. It invades the stomach and causes vomiting and diarrhea. It is known to come up into the host's mouth and poke its head out.
Try to grab it, and you choke for air, but let go and it returns peacefully to the stomach.
The herbs goshuyu (Euodia rutaecarpa), shazenshi and mokko are useful in fighting Kakuran-no-mushi.
In the Harikigaki
Japan’s Kyushu National Museum holds a copy of the Harikikigaki — a 16th century medical text of unknown authorship which claimed that diseases were caused by tiny bugs that crawled into the body. The Harikikigaki advises using acupuncture and herbs to deal with the bugs.
Until the late 19th century, Japanese people believed illness was spread by evil kami called yakubyogami. At first these gods were thought to take human form, but later, influenced by thinking in texts from China, some people came to think of them as little creatures as small enough to enter the body. The Harikikigaki, written in 1568, is mostly about acupuncture, however, this rare text includes 63 color depictions of the various mushi (germs) believed to cause diseases.