Morphological characteristics of the forestomach and reports of the natural diet suggest that dikdiks should have a ‘moose-type’ forestomach physiology with a low degree of selective particle retention. This assumption was tested in feeding experiments with 12 adult Phillip’s dikdiks (Madoqua saltiana phillipsi) on 3 different intake levels, using cobalt-EDTA as a solute marker and a conventional chromium-mordanted fibre (< 2mm; mean particle size 0.63mm) as particle marker. Body mass had no influence on retention time (RT) whereas food intake level clearly had. Drinking water intake was not related to solute marker RT. The particle marker was retained distinctively longer than the solute marker. Comparisons with results in larger ruminants and with faecal particle sizes measured in dikdiks suggested that the particle marker was above the critical size threshold, above which particle delay in the forestomach is not only due to selective particle retention, but additionally due to the ruminal particle sorting mechanism. A second study with a marker of a lower mean particle size (0.17mm) resulted in particle and fluid RT similar to those in other ‘moose-type’ ruminants. Even this smaller particle marker yielded RT that were longer than those predicted by allometric equations based on quarter-power scaling, providing further support for observations that small ruminants generally achieve longer RT and higher digestive efficiencies than expected based on their body size.