Biohazard OSRS Quick Guide

The Biohazard quest in Old School RuneScape (OSRS) is a thrilling continuation of the Plague City quest, diving deeper into the mystery of Ardougne’s plague. This novice-level quest is short, offers decent rewards, and unlocks useful features like the West Ardougne gate and King Lathas’ training ground. Whether you’re a new player or a seasoned adventurer, this SEO-optimized quick guide will walk you through every step to complete Biohazard efficiently. Let’s get started!

Prerequisites

Before starting Biohazard, you need to have completed the Plague City quest. There are no skill requirements, making it accessible for low-level players. However, you’ll need to defeat a level 13 Mourner, which is straightforward for most.

Step-by-Step Quest Walkthrough

Biohazard Quest Guide OSRS Guide

Starting the Quest

Head to East Ardougne and speak to Elena in her house, just west of the shortcut log and north of the pub. She’ll explain that the Mourners took her distillator, and she needs you to retrieve it from West Ardougne. Agree to help, and she’ll suggest talking to Jerico for assistance crossing the wall.

Crossing into West Ardougne

Follow these steps to get into West Ardougne:

Visit Jerico in his house south of the northern Ardougne bank. Search the cupboard inside for bird feed and grab a pigeon cage from behind his house.
Go to Omart, located west of Ceril Carnillean’s house, near the south-east corner of West Ardougne’s wall. He’ll mention the risk of crossing due to watchtower guards.
Head north to the watchtower along the wall. Stand where the spiked fences meet, use the bird feed on the fence (highlighted red on your minimap), and release the pigeons from the pigeon cage to distract the guards.
Speak to Omart again, and he’ll help you cross into West Ardougne.

Retrieving the Distillator

Once in West Ardougne, your goal is to recover Elena’s distillator:

Go to Nurse Sarah’s house, south-west of the West Ardougne church. Search the cupboard in the northern part of the house for a medical gown.
Equip the medical gown and head to the Mourner HQ in the north-east of West Ardougne. Enter the building (the gown allows access).
Go upstairs and attack a Mourner (level 13). Upon defeat, a key will automatically appear in your inventory. Skiller Tip: Use a ring of recoil to avoid dealing direct damage and gaining combat XP.
Use the key to unlock the caged room. Search the crate third from the left on the northern wall to find Elena’s distillator.
Return to Elena in East Ardougne (use Ardougne teleport, Skills necklace, or climb the mud pile via the manhole in West Ardougne). Hand over the distillator.

Smuggling Samples to Varrock

Collecting the Chemicals

Elena will give you liquid honey, ethenea, sulphuric broline, and a plague sample to deliver to Guidor in Varrock. She’ll also direct you to the chemist in Rimmington for touch paper.

Delivering to the Chemist

Travel to Rimmington (use Teleport to House if your house is there, Falador teleport, or Skills necklace to Crafting Guild). Visit the chemist in the westernmost building:

Tell the chemist you’re Elena’s friend and need touch paper for Guidor. He’ll hand it over.
Outside, give the chemicals to the chemist’s helpers: Chancy gets liquid honey, Da Vinci gets ethenea, and Hops gets sulphuric broline. Warning: Giving the wrong chemical to the wrong person means you’ll need to get replacements from Elena.
They’ll instruct you to meet them at the Dancing Donkey Inn in Varrock.

Getting Past Varrock Guards

Head to south-east Varrock’s fenced area with the plague sample and touch paper. Equip a priest gown set (buy from Asyff’s Fancy Clothes Store if needed). The guard will search you but allow the plague sample and touch paper through. If you forgot these items:

Drop the vials at the gate.
Run to Varrock east bank to retrieve the items.
Return and pick up the vials (Telekinetic Grab no longer works).

At the Dancing Donkey Inn, talk to Chancy, Da Vinci, and Hops to retrieve the vials. Then, go to Guidor’s house in the south-east corner of the fenced area. Equip the priest gown, speak to Guidor’s wife, and enter. Give Guidor the vials, sample, and touch paper, and tell him Elena sent you. He’ll analyze the sample and reveal a surprising truth about the plague.

Completing the Quest

Return to Ardougne and speak to Elena. She’ll be shocked by Guidor’s findings and suggest talking to King Lathas. Head to the 1st floor of Ardougne Castle (2nd floor in US terms) and speak to the king to complete the quest. Congratulations!

Rewards	Details
Quest Points	3
Thieving XP	1,250
Access	King Lathas’ training ground, West Ardougne gate
Teleport	West Ardougne Teleport (Arceuus spellbook)

Tips and Tricks for Efficiency

Optimizing Travel

Use teleports like Ardougne teleport or Skills necklace to save time. If you’re low on Magic, the manhole in West Ardougne is a reliable way back to East Ardougne. Energy potions are a lifesaver for running between locations.

Avoiding Common Mistakes

Here are pitfalls to watch out for:

Wrong vials: Double-check which chemical goes to each helper in Rimmington to avoid a trip back to Elena.
Inventory management: Keep at least 3 inventory spaces free when returning the distillator to Elena.
Guard confiscation: Don’t try to pass Varrock’s gate with vials unless wearing a priest gown, or they’ll be taken.

Skiller Strategies

For skillers avoiding combat XP, equip a ring of recoil when facing the Mourner. Talk to the Mourner to trigger the attack, let the ring do the damage, and the key will appear in your inventory without XP gain.