Two potential medical plants were examined of Marjoram (Majorana hortensis L. leaves) and black cumin (Nigella sativa L. seeds) to determine their suitability for supplementing cakes. Nutritional bioassay was done to evaluate 1 and 2% of M hortensis L. leaves and 1 and 2% of N sativa L. seeds powder compared with control in the experimental feeding of albino rats (six weeks age). The results showed that most of supplemented meals kept of their high nutritive values without any harmful effect on rat liver functions. However, 2% of M hortensis L. leaves utilized the best values in the nutritive measurements when compared to control and other supplied meals. The sensory evaluation of cakes supplemented with 1 and 2% of M hortensis L. leaves and 1 and 2% of N sativa L. seeds powder showed that there were no significant (p≤0.05) differences between control cake and supplemented samples as regard to texture and overall acceptability, except color and taste whereas the control was slightlymore acceptable (p≤ 0.05). On the other hand, there were no significant (p≤0.05) differences between the control and supplemented cakes as regard to protein, crude fiber and carbohydrate, except for 2% of each of N sativa L. seeds and M hortensis L. leaves which were the highest in total lipids, ash and polyphenol contents. As regard to essential and limiting amino acids, the addition of 1and 2% of each of M. hortensis L. leaves and N sativa L. seeds powders caused slight reductions in some essential amino acids. On the other hand, the 2% of M hortensis L. leaves powder was the best because it hasn't any limiting amino acids.