Well it certainly is not a placebo. It works whether you believe in it or not.
In fact Acupuncture is now often being used very effectively on animals by veterinarians in the western world.
And in China it is a standard treatment used on patients in comas to increase circulation, prevent bed sores and to keep organs functioning.
Obviously, babies and animals could have no preconceived ideas about Acupuncture and its' effectiveness.
When they heal from illnesses and ailments, this healing is caused purely by the physical and energetic effects of Acupuncture, therefore it is very real and cannot possibly be just a placebo effect.