diff --git a/src/mondata.c b/src/mondata.c
index 9151b2ec7..0b8136dcd 100644
--- a/src/mondata.c
+++ b/src/mondata.c
@@ -566,11 +566,14 @@ sticks(struct permonst *ptr)
 boolean
 cantvomit(struct permonst *ptr)
 {
-    /* rats and mice are incapable of vomiting;
+    /* rats and mice are incapable of vomiting; likewise with horses;
        which other creatures have the same limitation? */
     if (ptr->mlet == S_RODENT && ptr != &mons[PM_ROCK_MOLE]
         && ptr != &mons[PM_WOODCHUCK])
         return TRUE;
+    if (ptr == &mons[PM_WARHORSE] || ptr == &mons[PM_HORSE]
+        || ptr == &mons[PM_PONY])
+        return TRUE;
     return FALSE;
 }