The use of less impacting techniques in agricultural systems is the global trend, so the use of homeopathic preparations on these systems has been studied as ecologically sound technology. This study had the object to study the interaction between the homeopathic preparations and the development of Eucalyptus urophylla S. T. Blake seedlings and was conducted from May 2007 to July 2007, in the greenhouse of the Department of Plant Science at the Federal University of Viçosa, MG, Brazil. Applications were made in one-day intervals and preparations utilized were Phosphorus, Calcarea carbonica, Kali muriaticum, Magnesia carbonica, all in potencies 3CH and 12CH and the controls were water and alcohol 3CH. Parameters of seedlings quality were measured in different times during the experiment, up to the end. Kali muriaticum 12CH promoted increased root length of approximately 55% compared to the water control. Phosphorus 3CH differed from other treatments considering the total green mass. The homeopathic preparations Phosphorus 3CH and Kali muriaticum 12CH increased the root growth, in relation to controls. The responses obtained with the application of Phosphorus 3CH indicate the viability of its agronomic use to increase of the root capacity of absorbing elements, as much as necessary for the plant growth. (AU)