This is true, laughter is one of the best medicine.
Laughter decreases stress hormones and increases immune cells which fights infection, improves your resistance to diseases. It also triggers the release of endorphins. Endorphins promote an overall sense of well-being and can temporarily relieve pain, this was once said by @khus-knee (endorphins) on one of my blogs about depression
And always bear in mind that health is wealth our best investment.
I am glad that you have a good understanding of this topic!