diff --git a/src/alchemy.c b/src/alchemy.c
index aff3485ef..ca110d397 100644
--- a/src/alchemy.c
+++ b/src/alchemy.c
@@ -170,12 +170,6 @@ static int potion_luck(unit *u, region *r, attrib_type *atype, int amount) {
     return amount;
 }
 
-static int potion_truth(unit *u) {
-    UNUSED_ARG(u);
-    /* TODO: this potion does nothing! */
-    return 1;
-}
-
 static int potion_power(unit *u, int amount) {
     int use = u->number / 10;
     if (use < amount) {
@@ -201,9 +195,6 @@ static int do_potion(unit * u, region *r, const potion_type * ptype, int amount)
     else if (ptype == oldpotiontype[P_HORSE]) {
         return potion_luck(u, r, &at_horseluck, amount);
     }
-    else if (ptype == oldpotiontype[P_WAHRHEIT]) {
-        return potion_truth(u);
-    }
     else if (ptype == oldpotiontype[P_MACHT]) {
         return potion_power(u, amount);
     }
diff --git a/src/kernel/region.c b/src/kernel/region.c
index 81e9e4285..27936c79f 100644
--- a/src/kernel/region.c
+++ b/src/kernel/region.c
@@ -1060,7 +1060,10 @@ void terraform_region(region * r, const terrain_type * terrain)
     rawmaterial **lrm = &r->resources;
 
     assert(terrain);
-
+    if (r->units && fval(r->terrain, LAND_REGION) && !fval(terrain, LAND_REGION)) {
+        log_error("region %s contains units, not terraforming it to %s.", regionname(r, NULL), terrain->_name);
+        return;
+    }
     while (*lrm) {
         rawmaterial *rm = *lrm;
         const resource_type *rtype = NULL;