We are quite new to playing D&D and recently noticed that when you gain or lose constitution modifier, you will gain or lose hitpoints.

Now we are having a few issues with this, mainly being: What happens to a Level 5 character, with 5/25 HP and getting a -2 constitution modifier debuff. Will he be bleeding on the floor with a -5/15 hp? The same as when the debuff wears off, will the character that has -5/15 suddenly stop bleeding and be conscious with 5/25 hp again?

Currently the rulebook only states that a constitution modifier change will change your hp per hit dice and that your constitution modifier can not lower your max hp to less than 1 hp per hit dice.

Further, can a character die from constitution loss combined with previously attained damage? As in, I already have 50 damage on 70hp... will I die if I lose 20hp due to constitution loss?

  • \$\begingroup\$ Hello and welcome! You can take the tour for a quick site intro. I changed your title to be a bit more descriptive. If I misinterpreted what you were asking or you simply don't like the change feel free to revert or edit the question again. Thank you for the contribution and I hope you find the answer you seek. \$\endgroup\$
    – Sdjz
    Oct 8, 2018 at 14:33
  • \$\begingroup\$ I think this has already been answered here: rpg.stackexchange.com/questions/28851/… \$\endgroup\$ Oct 8, 2018 at 14:34
  • 3
    \$\begingroup\$ @JohnGoblin It may have the same answer but do note that the linked question is about 3.5e and this one is about 3e \$\endgroup\$
    – Sdjz
    Oct 8, 2018 at 14:36
  • \$\begingroup\$ @Sdjz yep, fair point! Pretty sure it's the same rule in both cases, for what its worth - this thread seems to support that: rpg.stackexchange.com/questions/69772/… \$\endgroup\$ Oct 8, 2018 at 14:39
  • \$\begingroup\$ @JohnGoblin: It answers the question but only with assumptions.. The way they describe it there I would happens as I describe. A character with 20 hp of damage, while loosing 10 max hp due to constitution modifier, will drop to -5hp/15. And thus when gaining constitution modifier, will regain consciousness without a form of healing. But it is not specifically stated! (No idea why my name is different here then on the question I asked) \$\endgroup\$ Oct 8, 2018 at 14:43

2 Answers 2


This is complicated, but it's unchanged by the 3.5 revision

Note: The effect of lowering a creature's Constitution ability score modifier is unchanged by the 3.5 revision. Likewise, the 3e quotations below were only barely changed—and not in any meaningful way—by the 3.5 revision (also see DMG (2003) 290 and here). This makes answers to this question also relevant. I've answered this question completely nonetheless in hopes that a different voice may clarify matters further.

The Dungeon Master's Guide (2000) on Ability Score Loss, in part, says

If a character’s Constitution score drops, then he loses 1 hit point per Hit Die for every point by which his Constitution modifier drops. For example, at 7th level, Tordek is hit by poison that causes his Constitution to drop from 16 to 13. His bonus falls from +3 to +1, so he loses 14 hit points (2 per level). A minute later, the poison deals another 8 points of temporary Constitution damage, dropping his score to 5 and his modifier from +1 to –3. He loses another 28 hit points—for a total of 42 hit points lost because of an overall 6-point drop in his Constitution modifier. (72)

It's the examples that make this really go. The DMG is, I think, trying here to simplify the process of reducing a creature's Constitution score, but, while doing so, it makes the process less clear and more complicated than it is. The DMG suggests that a creature treat its Constitution modifier reduction largely as hp damage even though it's actually not. (This reader suspects this is an effort to speed play.)

When a creature sees its Constitution score reduced by 1 or more points and this loss subsequently reduces the creature's Constitution modifier, the creature suffers a reduction to its maximum hp (that is, the hp the creature has when it's fully healed). The DMG's absolutely right that will totally look like hp damage to a point. However, that point is really important because a reduction in a creature's Constitution modifier doesn't technically deal the creature any points of damage.

For example, Arboc is level 5 and possesses Con 14 and 25 hp maximum but has been dealt 20 points of damage so that he currently has 5 hp. He's dealt 2 points of Constitution damage, lowering his Con 14 to Con 10 therefore his Con modifier from +2 to +0. His maximum hp go from 25 to 15. Arboc, having already been dealt 20 points of damage, is now at -5 hp and dying.

On Ability Score Loss continues, saying

A hit point score can’t be reduced by Constitution damage or drain to less than 1 hit point per Hit Die. At 7th level, Mialee has 22 hit points when fully healed. Even if her Constitution score drops to 5 or lower, she will still have at least 7 hit points (less any damage she may take). (ibid.)

…And this is why tracking Constitution ability score loss that reduces a creature's Constitution modifier as hp damage is an unfortunate recommendation. See, a creature just can't typically have its maximum hp reduced below 1 point per Hit Dice or level. Even when a creature stright-up dies from having its Constitution score reduced to 0, that creature's maximum hp still equal its Hit Dice or level.

For example, Arboc has his Con reduced to 1 yet previously has been dealt no damage. His maximum and current hp plummet but only to 5 (equal to his level) and not, for example, to −24 (i.e. 25 his normal maximum −(7 his level × 7 for his reduced Con modifier)). Arboc could even continue adventuring normally despite his Constitution score of 1, although he'd likely tread very carefully and hide in the middle of the party.

To continue this example, Arboc is level 5 and possesses Con 14 and 25 hp maximum but has been dealt 20 points of damage so that he currently has 5 hp. He's dealt 13 points of Constitution damage, lowering his Con 14 to Con 1 therefore his Con modifier from +2 to -5. His maximum hp go from 25 to 5. Arboc, having already been dealt 20 points of damage, is now at -15 hp and dead.

  • \$\begingroup\$ Awkward that when 0 CON is dead, but you have to change the modifier for characters with less than 5 hp per level so CON 1 is still alive. \$\endgroup\$
    – Wyrmwood
    Oct 8, 2018 at 19:24
  • \$\begingroup\$ @Wyrmwood I know! I wish the DMG (both editions!) had said first that a Con loss couldn't reduce a creature's maximum hp below its HD then explained how to actually adjust the creature's maximum hp. The order it's presented in is, indeed, awkward. \$\endgroup\$ Oct 8, 2018 at 19:33
  • \$\begingroup\$ Seems it would be easier to ignore the limit and let the frail die sooner. \$\endgroup\$
    – Wyrmwood
    Oct 8, 2018 at 19:46
  • \$\begingroup\$ @Wyrmwood I guess a DM could if she wanted a more lethal game. Such a decision makes, for example, traps that use poison deadlier, I guess, and and that may be a net improvement in the abstract. I don't know if it's really worth the time and trouble enshrining it in a DM's house rules, though, as it'll A) probably never come up, and B) if it does, everyone will have to be reminded about the rule, and C) then it'll probably just kill an already unlucky PC. \$\endgroup\$ Oct 8, 2018 at 20:02
  • \$\begingroup\$ I've always found managing ability score loss pretty much requires a spreadsheet for a character sheet. And that's without these corner case exceptions... \$\endgroup\$
    – Wyrmwood
    Oct 8, 2018 at 20:10

The Same Way They Affect Maximum HP

Changes to Constitution modifier immediately change both the current and maximum HP of the character. This change is why a raging Barbarian gains hit points immediately but can become Dying, or even Dead, at the end of the Rage.

For your example scenario, the character would drop to -5 current hit points and become Dying.

Edit: While I only referenced the 3.0 D&D rules, this is exactly the same as in the 3.5 edition rules. The effects of changes to Constitution modifiers remained unchanged when that alteration came out.


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