In Hindu astrology, Ketu is considered as the 7th planet from Sun. The 5th house represents people’s health and Ketu rules this area of life.
Ketu will have an effect on you if it is in the 5th house (from Sun) or its lord is placed there or aspected by Saturn/Moon.
If Ketu is placed in a natal chart, then it will give negative effects to the owner and also they would face obstacles while running their business. If Lord of Kethu (5th house) happens to be Saturn/Moon then the owner may face some kind of illness during their lifetime which can result in death if not treated properly.
Ketu is the sixth house lord in Vedic astrology. It is related to communication, speech and expression of thoughts. Ketu has a dominant position over its own sign which represents the last six houses of the horoscope. The house lord should have a good time period to rule these houses because they are prone to accidents and sudden losses due to miscommunication.
I hope this answers your question!