diff --git a/doc/fixes35.0 b/doc/fixes35.0
index 6b6667cdd..3ee77e4a0 100644
--- a/doc/fixes35.0
+++ b/doc/fixes35.0
@@ -68,6 +68,7 @@ when blind and levitating > shouldn't say "stairs" if player has not seen them
 a slow-moving monster hidden under a rotting corpse was not immediately
 	displayed when the corpse rotted away
 mimic that ends up on the rogue level should not mimic a closed door
+polymorphed or shapechanged monster sometimes got erroneous hit points
 
 
 Platform- and/or Interface-Specific Fixes
diff --git a/include/extern.h b/include/extern.h
index 0f4746482..2639e73a3 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -955,6 +955,7 @@ E void FDECL(readmail, (struct obj *));
 
 E boolean FDECL(is_home_elemental, (struct permonst *));
 E struct monst *FDECL(clone_mon, (struct monst *,XCHAR_P,XCHAR_P));
+E void FDECL(newmonhp, (struct monst *,int));
 E struct monst *FDECL(makemon, (struct permonst *,int,int,int));
 E boolean FDECL(create_critters, (int,struct permonst *));
 E struct permonst *NDECL(rndmonst);
diff --git a/src/makemon.c b/src/makemon.c
index 6a94826e8..2a7de4253 100644
--- a/src/makemon.c
+++ b/src/makemon.c
@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)makemon.c	3.4	2003/11/30	*/
+/*	SCCS Id: @(#)makemon.c	3.4	2004/05/21	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -802,6 +802,41 @@ boolean ghostly;
 	return result;
 }
 
+/* set up a new monster's initial level and hit points;
+   used by newcham() as well as by makemon() */
+void
+newmonhp(mon, mndx)
+struct monst *mon;
+int mndx;
+{
+    struct permonst *ptr = &mons[mndx];
+
+    mon->m_lev = adj_lev(ptr);
+    if (is_golem(ptr)) {
+	mon->mhpmax = mon->mhp = golemhp(mndx);
+    } else if (is_rider(ptr)) {
+	/* we want low HP, but a high mlevel so they can attack well */
+	mon->mhpmax = mon->mhp = d(10,8);
+    } else if (ptr->mlevel > 49) {
+	/* "special" fixed hp monster
+	 * the hit points are encoded in the mlevel in a somewhat strange
+	 * way to fit in the 50..127 positive range of a signed character
+	 * above the 1..49 that indicate "normal" monster levels */
+	mon->mhpmax = mon->mhp = 2 * (ptr->mlevel - 6);
+	mon->m_lev = mon->mhp / 4;	/* approximation */
+    } else if (ptr->mlet == S_DRAGON && mndx >= PM_GRAY_DRAGON) {
+	/* adult dragons */
+	mon->mhpmax = mon->mhp = (int) (In_endgame(&u.uz) ?
+		(8 * mon->m_lev) : (4 * mon->m_lev + d((int)mon->m_lev, 4)));
+    } else if (!mon->m_lev) {
+	mon->mhpmax = mon->mhp = rnd(4);
+    } else {
+	mon->mhpmax = mon->mhp = d((int)mon->m_lev, 8);
+	if (is_home_elemental(ptr))
+	    mon->mhpmax = (mon->mhp *= 3);
+    }
+}
+
 /*
  * called with [x,y] = coordinates;
  *	[0,0] means anyplace
@@ -904,30 +939,8 @@ register int	mmflags;
 	mtmp->mxlth = xlth;
 	mtmp->mnum = mndx;
 
-	mtmp->m_lev = adj_lev(ptr);
-	if (is_golem(ptr)) {
-	    mtmp->mhpmax = mtmp->mhp = golemhp(mndx);
-	} else if (is_rider(ptr)) {
-	    /* We want low HP, but a high mlevel so they can attack well */
-	    mtmp->mhpmax = mtmp->mhp = d(10,8);
-	} else if (ptr->mlevel > 49) {
-	    /* "special" fixed hp monster
-	     * the hit points are encoded in the mlevel in a somewhat strange
-	     * way to fit in the 50..127 positive range of a signed character
-	     * above the 1..49 that indicate "normal" monster levels */
-	    mtmp->mhpmax = mtmp->mhp = 2*(ptr->mlevel - 6);
-	    mtmp->m_lev = mtmp->mhp / 4;	/* approximation */
-	} else if (ptr->mlet == S_DRAGON && mndx >= PM_GRAY_DRAGON) {
-	    /* adult dragons */
-	    mtmp->mhpmax = mtmp->mhp = (int) (In_endgame(&u.uz) ?
-		(8 * mtmp->m_lev) : (4 * mtmp->m_lev + d((int)mtmp->m_lev, 4)));
-	} else if (!mtmp->m_lev) {
-	    mtmp->mhpmax = mtmp->mhp = rnd(4);
-	} else {
-	    mtmp->mhpmax = mtmp->mhp = d((int)mtmp->m_lev, 8);
-	    if (is_home_elemental(ptr))
-		mtmp->mhpmax = (mtmp->mhp *= 3);
-	}
+	/* set up level and hit points */
+	newmonhp(mtmp, mndx);
 
 	if (is_female(ptr)) mtmp->female = TRUE;
 	else if (is_male(ptr)) mtmp->female = FALSE;
diff --git a/src/mon.c b/src/mon.c
index 6312e6122..cf958b598 100644
--- a/src/mon.c
+++ b/src/mon.c
@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)mon.c	3.4	2003/12/04	*/
+/*	SCCS Id: @(#)mon.c	3.4	2004/05/21	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -2372,7 +2372,7 @@ struct permonst *mdat;
 boolean polyspot;	/* change is the result of wand or spell of polymorph */
 boolean msg;		/* "The oldmon turns into a newmon!" */
 {
-	int mhp, hpn, hpd;
+	int hpn, hpd;
 	int mndx, tryct;
 	struct permonst *olddata = mtmp->data;
 	char oldname[BUFSZ], newname[BUFSZ];
@@ -2432,32 +2432,24 @@ boolean msg;		/* "The oldmon turns into a newmon!" */
 		place_monster(mtmp, mtmp->mx, mtmp->my);
 	}
 
+	/* (this code used to try to adjust the monster's health based on
+	   a normal one of its type but there are too many special cases
+	   which need to handled in order to do that correctly, so just
+	   give the new form the same proportion of HP as its old one had) */
 	hpn = mtmp->mhp;
-	hpd = (mtmp->m_lev < 50) ? ((int)mtmp->m_lev)*8 : mdat->mlevel;
-	if(!hpd) hpd = 4;
-
-	mtmp->m_lev = adj_lev(mdat);		/* new monster level */
-
-	mhp = (mtmp->m_lev < 50) ? ((int)mtmp->m_lev)*8 : mdat->mlevel;
-	if(!mhp) mhp = 4;
-
+	hpd = mtmp->mhpmax;
+	/* set level and hit points */
+	newmonhp(mtmp, monsndx(mdat));
 	/* new hp: same fraction of max as before */
 #ifndef LINT
-	mtmp->mhp = (int)(((long)hpn*(long)mhp)/(long)hpd);
+	mtmp->mhp = (int)(((long)hpn * (long)mtmp->mhp) / (long)hpd);
 #endif
-	if(mtmp->mhp < 0) mtmp->mhp = hpn;	/* overflow */
-/* Unlikely but not impossible; a 1HD creature with 1HP that changes into a
-   0HD creature will require this statement */
+	/* sanity check (potentional overflow) */
+	if (mtmp->mhp < 0 || mtmp->mhp > mtmp->mhpmax) mtmp->mhp = mtmp->mhpmax;
+	/* unlikely but not impossible; a 1HD creature with 1HP that changes
+	   into a 0HD creature will require this statement */
 	if (!mtmp->mhp) mtmp->mhp = 1;
 
-/* and the same for maximum hit points */
-	hpn = mtmp->mhpmax;
-#ifndef LINT
-	mtmp->mhpmax = (int)(((long)hpn*(long)mhp)/(long)hpd);
-#endif
-	if(mtmp->mhpmax < 0) mtmp->mhpmax = hpn;	/* overflow */
-	if (!mtmp->mhpmax) mtmp->mhpmax = 1;
-
 	/* take on the new form... */
 	set_mon_data(mtmp, mdat, 0);