diff --git a/code/modules/organs/internal/appendix.dm b/code/modules/organs/internal/appendix.dm
new file mode 100644
index 00000000000..b3fdc28bc2d
--- /dev/null
+++ b/code/modules/organs/internal/appendix.dm
@@ -0,0 +1,55 @@
+#define PROCESS_ACCURACY 10
+
+/obj/item/organ/internal/appendix
+	name = "appendix"
+	icon_state = "appendix"
+	parent_organ = BP_GROIN
+	organ_tag = "appendix"
+	var/inflamed = 0
+	var/inflame_progress = 0
+
+/mob/living/carbon/human/proc/appendicitis()
+	if(stat == DEAD)
+		return 0
+	var/obj/item/organ/internal/appendix/A = internal_organs_by_name[O_APPENDIX]
+	if(istype(A) && !A.inflamed)
+		A.inflamed = 1
+		return 1
+	return 0
+
+/obj/item/organ/internal/appendix/process()
+	if(!inflamed || !owner)
+		return
+
+	if(++inflame_progress > 200)
+		++inflamed
+		inflame_progress = 0
+
+	if(inflamed == 1)
+		if(prob(5))
+			owner << "<span class='warning'>You feel a stinging pain in your abdomen!</span>"
+			owner.emote("me", 1, "winces slightly.")
+	if(inflamed > 1)
+		if(prob(3))
+			owner << "<span class='warning'>You feel a stabbing pain in your abdomen!</span>"
+			owner.emote("me", 1, "winces painfully.")
+			owner.adjustToxLoss(1)
+	if(inflamed > 2)
+		if(prob(1))
+			owner.vomit()
+	if(inflamed > 3)
+		if(prob(1))
+			owner << "<span class='danger'>Your abdomen is a world of pain!</span>"
+			owner.Weaken(10)
+
+			var/obj/item/organ/external/groin = owner.get_organ(BP_GROIN)
+			var/datum/wound/W = new /datum/wound/internal_bleeding(20)
+			owner.adjustToxLoss(25)
+			groin.wounds += W
+			inflamed = 0
+
+/obj/item/organ/internal/appendix/removed()
+	if(inflamed)
+		icon_state = "appendixinflamed"
+		name = "inflamed appendix"
+	..()
\ No newline at end of file
diff --git a/code/modules/organs/internal/eyes.dm b/code/modules/organs/internal/eyes.dm
new file mode 100644
index 00000000000..ddde8726620
--- /dev/null
+++ b/code/modules/organs/internal/eyes.dm
@@ -0,0 +1,78 @@
+#define PROCESS_ACCURACY 10
+
+/obj/item/organ/internal/eyes
+	name = "eyeballs"
+	icon_state = "eyes"
+	gender = PLURAL
+	organ_tag = O_EYES
+	parent_organ = BP_HEAD
+	var/list/eye_colour = list(0,0,0)
+
+/obj/item/organ/internal/eyes/robotize()
+	..()
+	name = "optical sensor"
+	icon = 'icons/obj/robot_component.dmi'
+	icon_state = "camera"
+	dead_icon = "camera_broken"
+	verbs |= /obj/item/organ/internal/eyes/proc/change_eye_color
+
+/obj/item/organ/internal/eyes/robot
+	name = "optical sensor"
+
+/obj/item/organ/internal/eyes/robot/New()
+	..()
+	robotize()
+
+/obj/item/organ/internal/eyes/proc/change_eye_color()
+	set name = "Change Eye Color"
+	set desc = "Changes your robotic eye color instantly."
+	set category = "IC"
+	set src in usr
+
+	var/current_color = rgb(eye_colour[1],eye_colour[2],eye_colour[3])
+	var/new_color = input("Pick a new color for your eyes.","Eye Color", current_color) as null|color
+	if(new_color && owner)
+		// input() supplies us with a hex color, which we can't use, so we convert it to rbg values.
+		var/list/new_color_rgb_list = hex2rgb(new_color)
+		// First, update mob vars.
+		owner.r_eyes = new_color_rgb_list[1]
+		owner.g_eyes = new_color_rgb_list[2]
+		owner.b_eyes = new_color_rgb_list[3]
+		// Now sync the organ's eye_colour list.
+		update_colour()
+		// Finally, update the eye icon on the mob.
+		owner.update_eyes()
+
+/obj/item/organ/internal/eyes/replaced(var/mob/living/carbon/human/target)
+
+	// Apply our eye colour to the target.
+	if(istype(target) && eye_colour)
+		target.r_eyes = eye_colour[1]
+		target.g_eyes = eye_colour[2]
+		target.b_eyes = eye_colour[3]
+		target.update_eyes()
+	..()
+
+/obj/item/organ/internal/eyes/proc/update_colour()
+	if(!owner)
+		return
+	eye_colour = list(
+		owner.r_eyes ? owner.r_eyes : 0,
+		owner.g_eyes ? owner.g_eyes : 0,
+		owner.b_eyes ? owner.b_eyes : 0
+		)
+
+/obj/item/organ/internal/eyes/take_damage(amount, var/silent=0)
+	var/oldbroken = is_broken()
+	..()
+	if(is_broken() && !oldbroken && owner && !owner.stat)
+		owner << "<span class='danger'>You go blind!</span>"
+
+/obj/item/organ/internal/eyes/process() //Eye damage replaces the old eye_stat var.
+	..()
+	if(!owner)
+		return
+	if(is_bruised())
+		owner.eye_blurry = 20
+	if(is_broken())
+		owner.eye_blind = 20
\ No newline at end of file
diff --git a/code/modules/organs/internal/heart.dm b/code/modules/organs/internal/heart.dm
new file mode 100644
index 00000000000..99b7386403e
--- /dev/null
+++ b/code/modules/organs/internal/heart.dm
@@ -0,0 +1,8 @@
+#define PROCESS_ACCURACY 10
+
+/obj/item/organ/internal/heart
+	name = "heart"
+	icon_state = "heart-on"
+	organ_tag = O_HEART
+	parent_organ = BP_TORSO
+	dead_icon = "heart-off"
\ No newline at end of file
diff --git a/code/modules/organs/internal/kidneys.dm b/code/modules/organs/internal/kidneys.dm
new file mode 100644
index 00000000000..5d3875ccf54
--- /dev/null
+++ b/code/modules/organs/internal/kidneys.dm
@@ -0,0 +1,25 @@
+#define PROCESS_ACCURACY 10
+
+/obj/item/organ/internal/kidneys
+	name = "kidneys"
+	icon_state = "kidneys"
+	gender = PLURAL
+	organ_tag = O_KIDNEYS
+	parent_organ = BP_GROIN
+
+/obj/item/organ/internal/kidneys/process()
+
+	..()
+
+	if(!owner)
+		return
+
+	// Coffee is really bad for you with busted kidneys.
+	// This should probably be expanded in some way, but fucked if I know
+	// what else kidneys can process in our reagent list.
+	var/datum/reagent/coffee = locate(/datum/reagent/drink/coffee) in owner.reagents.reagent_list
+	if(coffee)
+		if(is_bruised())
+			owner.adjustToxLoss(0.1 * PROCESS_ACCURACY)
+		else if(is_broken())
+			owner.adjustToxLoss(0.3 * PROCESS_ACCURACY)
\ No newline at end of file
diff --git a/code/modules/organs/internal/liver.dm b/code/modules/organs/internal/liver.dm
new file mode 100644
index 00000000000..ef989b7a558
--- /dev/null
+++ b/code/modules/organs/internal/liver.dm
@@ -0,0 +1,55 @@
+#define PROCESS_ACCURACY 10
+
+/obj/item/organ/internal/liver
+	name = "liver"
+	icon_state = "liver"
+	organ_tag = "liver"
+	parent_organ = BP_GROIN
+
+/obj/item/organ/internal/liver/process()
+
+	..()
+
+	if(!owner)
+		return
+
+	if (germ_level > INFECTION_LEVEL_ONE)
+		if(prob(1))
+			owner << "<span class='danger'>Your skin itches.</span>"
+	if (germ_level > INFECTION_LEVEL_TWO)
+		if(prob(1))
+			spawn owner.vomit()
+
+	if(owner.life_tick % PROCESS_ACCURACY == 0)
+
+		//High toxins levels are dangerous
+		if(owner.getToxLoss() >= 60 && !owner.reagents.has_reagent("anti_toxin"))
+			//Healthy liver suffers on its own
+			if (src.damage < min_broken_damage)
+				src.damage += 0.2 * PROCESS_ACCURACY
+			//Damaged one shares the fun
+			else
+				var/obj/item/organ/internal/O = pick(owner.internal_organs)
+				if(O)
+					O.damage += 0.2  * PROCESS_ACCURACY
+
+		//Detox can heal small amounts of damage
+		if (src.damage && src.damage < src.min_bruised_damage && owner.reagents.has_reagent("anti_toxin"))
+			src.damage -= 0.2 * PROCESS_ACCURACY
+
+		if(src.damage < 0)
+			src.damage = 0
+
+		// Get the effectiveness of the liver.
+		var/filter_effect = 3
+		if(is_bruised())
+			filter_effect -= 1
+		if(is_broken())
+			filter_effect -= 2
+
+		// Do some reagent processing.
+		if(owner.chem_effects[CE_ALCOHOL_TOXIC])
+			if(filter_effect < 3)
+				owner.adjustToxLoss(owner.chem_effects[CE_ALCOHOL_TOXIC] * 0.1 * PROCESS_ACCURACY)
+			else
+				take_damage(owner.chem_effects[CE_ALCOHOL_TOXIC] * 0.1 * PROCESS_ACCURACY, prob(1)) // Chance to warn them
\ No newline at end of file
diff --git a/code/modules/organs/internal/lungs.dm b/code/modules/organs/internal/lungs.dm
new file mode 100644
index 00000000000..fae4bc5ee6b
--- /dev/null
+++ b/code/modules/organs/internal/lungs.dm
@@ -0,0 +1,26 @@
+#define PROCESS_ACCURACY 10
+
+/obj/item/organ/internal/lungs
+	name = "lungs"
+	icon_state = "lungs"
+	gender = PLURAL
+	organ_tag = O_LUNGS
+	parent_organ = BP_TORSO
+
+/obj/item/organ/internal/lungs/process()
+	..()
+
+	if(!owner)
+		return
+
+	if (germ_level > INFECTION_LEVEL_ONE)
+		if(prob(5))
+			owner.emote("cough")		//respitory tract infection
+
+	if(is_bruised())
+		if(prob(2))
+			spawn owner.emote("me", 1, "coughs up blood!")
+			owner.drip(10)
+		if(prob(4))
+			spawn owner.emote("me", 1, "gasps for air!")
+			owner.losebreath += 15
\ No newline at end of file
diff --git a/code/modules/organs/internal/organ_internal.dm b/code/modules/organs/internal/organ_internal.dm
new file mode 100644
index 00000000000..100666caaaa
--- /dev/null
+++ b/code/modules/organs/internal/organ_internal.dm
@@ -0,0 +1,36 @@
+#define PROCESS_ACCURACY 10
+
+/****************************************************
+				INTERNAL ORGANS DEFINES
+****************************************************/
+/obj/item/organ/internal
+	var/dead_icon // Icon to use when the organ has died.
+
+/obj/item/organ/internal/die()
+	..()
+	if((status & ORGAN_DEAD) && dead_icon)
+		icon_state = dead_icon
+
+/obj/item/organ/internal/Destroy()
+	if(owner)
+		owner.internal_organs.Remove(src)
+		owner.internal_organs_by_name[organ_tag] = null
+		owner.internal_organs_by_name -= organ_tag
+		while(null in owner.internal_organs)
+			owner.internal_organs -= null
+		var/obj/item/organ/external/E = owner.organs_by_name[parent_organ]
+		if(istype(E)) E.internal_organs -= src
+	return ..()
+
+/obj/item/organ/internal/remove_rejuv()
+	if(owner)
+		owner.internal_organs -= src
+		owner.internal_organs_by_name[organ_tag] = null
+		owner.internal_organs_by_name -= organ_tag
+		while(null in owner.internal_organs)
+			owner.internal_organs -= null
+		var/obj/item/organ/external/E = owner.organs_by_name[parent_organ]
+		if(istype(E)) E.internal_organs -= src
+	..()
+
+// Brain is defined in brain_item.dm.
\ No newline at end of file
diff --git a/polaris.dme b/polaris.dme
index aa6ae25e6d9..352bf17d265 100644
--- a/polaris.dme
+++ b/polaris.dme
@@ -1664,11 +1664,17 @@
 #include "code\modules\organs\organ.dm"
 #include "code\modules\organs\organ_external.dm"
 #include "code\modules\organs\organ_icon.dm"
-#include "code\modules\organs\organ_internal.dm"
 #include "code\modules\organs\organ_stump.dm"
 #include "code\modules\organs\pain.dm"
 #include "code\modules\organs\robolimbs.dm"
 #include "code\modules\organs\wound.dm"
+#include "code\modules\organs\internal\appendix.dm"
+#include "code\modules\organs\internal\eyes.dm"
+#include "code\modules\organs\internal\heart.dm"
+#include "code\modules\organs\internal\kidneys.dm"
+#include "code\modules\organs\internal\liver.dm"
+#include "code\modules\organs\internal\lungs.dm"
+#include "code\modules\organs\internal\organ_internal.dm"
 #include "code\modules\organs\subtypes\diona.dm"
 #include "code\modules\organs\subtypes\machine.dm"
 #include "code\modules\organs\subtypes\seromi.dm"