Homeopathy is a complementary Medicine System founded over 230 years ago by Samuel Hahnemann M.D. based on the concept of Simillimum. Simply put, that which causes symptoms in a healthy individual has the power to resolve those same symptoms in a dis-eased state.  
Rather than overpowering the body's healing mechanism (by suppressing a natural body function, or stimulating one which your body is unable to sustain), homeopathy works with your body to support it and empower it to find a natural balance and strength, with no long-term harmful side effects, making it ideal for all ages. 
Homeopathic remedies are prepared through a precise sequence of measured dilution and 'potentisation' which eliminates any toxicity whilst preserving any health promoting qualities.
Hahnemann was a gifted physician, fluent in ten languages, son of a porcelain painter he was a perfectionist with a fascination for the 'biological sciences'. His parents could not afford to send him to medical school, so he paid for it himself by translating and by teaching languages. He studied in Leipzig before moving to Vienna to complete his education, graduating from the University of Erlangen in1779, at age 24.
Against this backdrop, this talented and passionate physician became disillusioned by the medical practices of the day, which were largely made up of superstitions and illogical practices which worsened the patients' symptoms - blood-letting, leeching, mercury, and arsenic among the most frequent methods employed. Seeing these options as barbaric and inhumane, Hahnemann decided that he could not be part of a medical system which harms patients. Determined to find another way of treating the sick without causing more harm, he closed his medical practice, translating scientific and medical texts and textbooks to feed his large family (11 children) and developing the system which would become known as Homeopathy.
It was whilst translating William Cullen's 'A Treatise on Materia Medica' when Hahnemann was dissatisfied with an explanation about WHY Peruvian Bark (Cinchona - the source of quinine) is successful against malaria, that Hahnemann performed what can arguably be called the first true clinical trial on himself. In his quest for true understanding, he ingested repeated doses of Cinchona and observed its effects, recording these diligently. What he found was that he began to develop symptoms that mimicked those of malaria, which reinforced the concept of Simillimum as mentioned in historical writings by early healers such as Swiss physician Paracelsus in the first half of the 1500s.
From then Hahnemann worked tirelessly on his new medical system, conducting these clinical trials which he called 'provings' on himself, his wife and children, and even close friends. 
Hahnemann wanted to find a methodology that would promote the resolution of disease symptoms without harmful side effects. He established that through dilution alone he could not remove the toxic properties of substances, and whether by chance or design, he discovered that if he 'succussed' the diluted remedy this produced in his patients a marked improvement and none of the harmful side effects. Also, through this method, he was able to dilute much more and yet still maintain, nay amplify, the healing properties. Research has since revealed that this produces nano-particles of the substances, which can still be detected well above the Avogadro's number.