Apart from efficacy and toxicity, many drug development failures are imputable to poor pharmacokinetics and bioavailability. Gastrointestinal absorption and brain access are two pharmacokinetic behaviors crucial to estimate at various stages of the drug discovery processes. To this end, the Brain Or IntestinaL EstimateD permeation method (BOILED‐Egg) is proposed as an accurate predictive model that works by computing the lipophilicity and polarity of small molecules. Concomitant predictions for both brain and intestinal permeation are obtained from the same two physicochemical descriptors and straightforwardly translated into molecular design, owing to the speed, accuracy, conceptual simplicity and clear graphical output of the model. The BOILED‐Egg can be applied in a variety of settings, from the filtering of chemical libraries at the early steps of drug discovery, to the evaluation of drug candidates for development. Sunny side up: An outstandingly intuitive model is proposed for the simultaneous estimation of brain access and gastrointestinal absorption of molecules by computing just two simple physicochemical descriptors. Along with its statistical robustness, the graphical nature and speed of the method enable efficient translation into molecular design. As a result, this BOILED‐Egg has proven highly practical in the context of drug discovery and medicinal chemistry.