The Peace Terms of which Treaty is being referred to in the cartoon given below? Who had to swallow the bitter pills and why?

The Peace terms of the Treaty of Versailles (June 28, 1919) are being referred to in the given cartoon picture. Germany had to swallow the bitter pills.

The Treaty of Versailles aimed to prevent Germany from going to war again by limiting its military strength, taking away territories, imposing war guilt, and enforcing heavy reparations. These terms crippled Germany militarily and economically.