Phenolic compounds are secondary metabolites in plants. Wine contains a large array of these compounds. Factors contributing to phenolic composition in wines are varietal type, cluster light exposure, maceration techniques, and cooperage. They are also important compounds in that they contribute to color and sensory properties like bitterness and astringency. Epidemiological studies have shown phenolics to have strong correlations with decreased incidences of cancer in certain populations. The identification of a specific phenolic compound, or class of compounds that are able inhibit certain cancer processes would give a better understanding of how certain cancers may be prevented by dietary intervention. This is a difficult task since cancer is not a simple process, but a series of sequential steps of initiation, development, and progression with no specific length of time associated with each step. Using experimental models, like transgenic mice, which will develop a tumor at approximately 75 days of age, it is possible to show a specific cause and effect relationship between dietary supplements and tumor development. Red wines' matrix of phenolics makes it an ideal medium to study phenolics' effects on this tumor process. The objective of this study was to determine if wine contains a specific compound, or class of compounds that may be responsible for delay of a tumor development. The discovery of such compounds would encourage research of winemaking techniques which could be carried out to maximize health benefits. A wine was analyzed for total phenolics, and for eight specific compounds, gallic acid, caffeic acid, catechin, epicatechin, malvidin-3-glucoside, quercetin, myricetin and resveratrol (a stilbene). It was then fractionated into four main phenolic classes, phenolic acids, flavonoids, flavonols, and polymeric phenols. These wine fractions, in addition to a low moisture prune powder that is rich in phenolic acids, and the whole wine, which was not fractionated, were then respectively included into separate treatment groups of tax 1 transgenic mice. It was shown that there was not a significant difference in tumor onset between any of the diet treatment groups. These findings, in addition to the results from previous research projects using the same model, suggest that any delayed tumor onset may be the result of a specific compound, or class of compounds. Relationships between maceration techniques of different red wines seem to be an important factor to consider, and all red wines should not be treated equally when generalizing their relationship with overall positive health benefits.