A capsule includes a casing provided with a base wall and with a side wall defining an open cavity for containing a product to be combined with a fluid to produce a final product. The base wall has such a thickness as to be perforable. The capsule further includes a stiffening element connected with an inner surface of the base wall within the cavity to stiffen the base wall. The base wall includes at least one through opening at a preset portion to be perforated for the outflow of the final product.