My son and my daughter both had this and they were miserable. I went out and found anything I could to help treat this and I really think it helped.
I got a homeopathic remedy of Cocksackie Virus (Hand foot and mouth disease) and gave this to them and it really seemed to help relieve the symptoms faster than my sisters kids who had nothing. You can order the remedy from the Hanna Kruger website http://www.hannasherbshop.com/ or get it from a Naturopathic doctor.
I also had my kids on black walnut tincture to help kill the virus and this seemed to help as well. Good luck! : D
It is advisable to have them on the medication administered to them by their pediatrician. If they have trouble eating, give them several small meals in a day. The disease usually lasts between five to seven days however; the duration of the appearance of the symptoms might be longer. For more information on the disease, visit http://children.webmd.com/tc/hand-foot-and-mouth-disease-topic-overview.