diff --git a/doc/fixes37.0 b/doc/fixes37.0
index 8cbba5056..bf067b452 100644
--- a/doc/fixes37.0
+++ b/doc/fixes37.0
@@ -465,6 +465,10 @@ contents of chests, large boxes, and ice boxes are now immune to water damage
 	chests+large boxes were always immune and ice boxes always vulnerable)
 applying an empty brass lantern in an attempt to light it reported "your lamp
 	has run out of power"; change to "your lantern is out of power"
+when swallowed or underwater, player could be told about events (such as a
+	shapechanger taking on a new form) that the hero sensed but which
+	were not shown on the screen; treat being swallowed or underwater as
+	situations which block telepathy, extended monster detection, warning
 
 
 Fixes to 3.7.0-x Problems that Were Exposed Via git Repository
diff --git a/include/display.h b/include/display.h
index e3fa0d816..a32469c89 100644
--- a/include/display.h
+++ b/include/display.h
@@ -38,6 +38,11 @@ enum explosion_types {
  *
  * Returns true if the hero can sense the given monster.  This includes
  * monsters that are hiding or mimicing other monsters.
+ *
+ * [3.7] Note: the map doesn't display any monsters when hero is swallowed
+ * (or display non-adjacent, non-submerged ones when hero is underwater),
+ * so treat those situations as blocking telepathy, detection, and warning
+ * even though conceptually they shouldn't do so.
  */
 #define tp_sensemon(mon) \
     (/* The hero can always sense a monster IF:        */  \
@@ -49,15 +54,19 @@ enum explosion_types {
           /*        object and in range                */  \
           || (Unblind_telepat                              \
               && (distu(mon->mx, mon->my) <= (BOLT_LIM * BOLT_LIM)))))
-
+/* organized to perform cheaper tests first;
+   is_pool() vs is_pool_or_lava(): hero who is underwater can see adjacent
+   lava, but presumeably any monster there is on top so not sensed */
 #define sensemon(mon) \
-    (tp_sensemon(mon) || Detect_monsters || MATCH_WARN_OF_MON(mon))
+    (   (!u.uswallow || (mon) == u.ustuck)                                 \
+     && (!Underwater || (distu((mon)->mx, (mon)->my) <= 2                  \
+                         && is_pool((mon)->mx, (mon)->my)))                \
+     && (Detect_monsters || tp_sensemon(mon) || MATCH_WARN_OF_MON(mon))   )
 
 /*
  * mon_warning() is used to warn of any dangerous monsters in your
  * vicinity, and a glyph representing the warning level is displayed.
  */
-
 #define mon_warning(mon)                                                 \
     (Warning && !(mon)->mpeaceful && (distu((mon)->mx, (mon)->my) < 100) \
      && (((int) ((mon)->m_lev / 4)) >= g.context.warnlevel))
diff --git a/src/potion.c b/src/potion.c
index 22c21c060..516f4d9bd 100644
--- a/src/potion.c
+++ b/src/potion.c
@@ -826,10 +826,13 @@ peffects(struct obj *otmp)
                         g.potion_unkn = 0;
                 }
             }
-            see_monsters();
-            if (g.potion_unkn)
-                You_feel("lonely.");
-            break;
+            /* if swallowed or underwater, fall through to uncursed case */
+            if (!u.uswallow && !Underwater) {
+                see_monsters();
+                if (g.potion_unkn)
+                    You_feel("lonely.");
+                break;
+            }
         }
         if (monster_detect(otmp, 0))
             return 1; /* nothing detected */