It took decades for science to take note of the alarming increase in inflammatory diseases and to intensively investigate the causes. Initially, it was believed that the decline in infections was responsible for the sharp increase in cases of disease (“hygiene hypothesis”), after which the importance of environmental bacteria as an inflammation brake (“farm effect”) was recognized. Today, the anti-inflammatory effect of the microbiome is the focus of attention. These three explanations for the increase in inflammatory diseases do not contradict each other; on the contrary, they complement each other: All agree that, without certain, dampening signals from bacteria, the human immune system is misprogrammed, runs too high and tends towards inflammation.