Abstract: Manual piston pump having a blockable dispensing head for dispensing fluid substances, having a cylinder, an inner locking sleeve forming a cylindrical passage for a hollow piston rod to pass through, one end of this extending into a pump chamber of the cylinder and the other end carrying the dispensing head, which is provided with an outer shaft section, a spring which presses the piston rod outwards in relation to the cylinder, into a rest position, and in opposition to the spring force whereof the piston rod may be lowered by pressing on the dispensing head in order to dispense substance, and having a means for blocking the dispensing head, this means including at least one locking element which may be brought into engagement with the locking sleeve, in which, together with the piston rod (6), the locking sleeve (5) forms an inner cage (18) for receiving the spring (19), which is supported at one end against a base (20) of the locking sleeve (5) and at the other against the locking element (21) provided on