Are there any negative side effects of ritalin (methylphenidate) on a ten year old child?

Maybe. All medications have side effects. Please be sure to discuss the risks and benefits of any prescribed medications with your physician and pharmacist. Be informed and also read the package insert that comes with the medication. Good luck.
Potential side effec. the most common side effects include headache, stomach ache, irritability, depression, anxiety, decreased appetite, usually for lunch, tics and dificulty getting to sleep in the evening. Side effects occur in about 5-10% of children who take Ritalin (methylphenidate). In many cases, the side effects subside after a few days, leaving somewhat less than 5% with persistent side effects.
Side effects. Make sure DX correct ( ie not treating behavioral problems with stimulant) decreased appetite with negative effects on growth & weight impaired sleep are main ones.